Since the formal establishment of the Xia Dynasty, China has experienced many dynasties, until the end of the Qing Dynasty, from the establishment of the Great Qin Empire by Qin Shi Huang, no matter which dynasty can not exceed the 300-year mark, and in contrast, korea has appeared as much as 400 years of the Lee Dynasty, and the Japanese imperial family is still circulating until now.

Why is this happening, is it that the ancient dynasties were not strong enough? Except for the late Qing Dynasty, China's ancient dynasties are basically ahead of the world, and the reason why China's ancient dynasties are short-lived has multiple reasons.
Characteristic of ancient dynasties
The biggest difference between china's ancient dynasties and Western dynasties lies in power, China's ancient dynasties believe in centralized power, excluding special periods such as Cixi, the emperor alone has a very powerful power, which can directly determine the direction of a country.
In this way of power distribution, if there is an excellent emperor, the country will be greatly developed, such as Emperor Wu of Han, Tang Taizong, etc., but if a very "inferior" emperor appears, the country will have a crisis at any time.
Not only that, too much centralized power leads to very serious internal problems, and the princes and grandchildren, foreign relatives, local tyrants, etc. who belong to the collateral clan will all look at the throne, so although the reasons for the decline of ancient dynasties are completely different, in the final analysis, it is because the power is too concentrated.
If the average life expectancy of an emperor is 40 years, then in 300 years, there will be about 8 emperors, and a few dynasties will experience more than ten emperors, and during the reign of these emperors, they will face many problems: foreign relatives, princes, ministers, foreign tribes, former courtiers, etc. As long as one emperor drops the chain, the dynasty will be overthrown.
Attacks by foreign enemies
In history, there are many dynasties that have been defeated by foreign enemies, the most representative of which are the Song Dynasty and the Ming Dynasty, and frankly speaking, these two dynasties are still very strong, but in the change of emperors, loopholes gradually appear, resulting in the gradual decay of the country.
At the same time, foreign enemies are constantly getting stronger, especially the Song Dynasty, the song Dynasty faced a strong enemy Mongolia was the most powerful nation in the world at that time, not only the Song Dynasty, the entire European region was helpless in the face of Mongolian attacks, if it were not for the sudden death of Genghis Khan, the leader of Mongolia at the time, Europe might no longer exist.
The ming dynasty faced a strong enemy Houjin was also the overlord of Guanwai at that time, they not only conquered the powerful Mongols, but also conquered other ethnic groups on the steppe, but the fall of the Ming Dynasty was not only an attack by foreign enemies in the strict sense, but also the uprising of Li Zicheng inside, and the betrayal of the Ming general Wu Sangui, which completely plunged the Ming Dynasty into a desperate situation.
The attack of foreign enemies mainly tests the strength of the country and the ability of the current emperor, which is a coincidental event, in the change of emperors, not every emperor has the ability to face a strong enemy, for example, during the Han Dynasty, Emperor Wen of Han and Emperor Jing of Han after Liu Bang did not have the strength to face strong enemies.
If the Xiongnu chose to attack, there was a great possibility of defeating the Han Dynasty, but the Xiongnu chose to give up, and when emperor Wudi of Han came out of nowhere, the Xiongnu understood the need to attack, but in the face of Emperor Wudi of Han, they had no advantage and became the stepping stone of Emperor Wudi of Han.
Its own problem
Different from foreign enemies, as an emperor, you also need to face some enemies from different directions, the most important thing to pay attention to is the foreign relatives, the end of the Western Han Dynasty is the problem of foreign relatives usurping the throne, in the same way, with the decline of the dynasty step by step, the domestic big families will also look at the tiger, such as the Sui Dynasty, the overthrow of the Sui Dynasty is the domestic big family Yuwen family.
In fact, the change of dynasties is inevitable from a historical point of view, no one will allow others to hold power alone, where there is power, there will be war, especially in ancient centralization, the existence of emperors, which means that some people are inferior from birth, this kind of thing is not acceptable to everyone.
So how to prevent this situation, there are only two ways to solve, one is the decentralization of imperial power, the most typical of which is the British royal family and the Japanese royal family, these two royal families have a common feature, that is, there is no actual power, only some symbolic significance.
Taking the Japanese imperial family as an example, the Japanese imperial family only has symbolic power and representation in Japan, they can make calls, but they cannot make decisions, so they will not be hostile, because the people in power are not them, and the various families in the country will not be regulated, and naturally they will not mind their existence.
This is very similar to the late Eastern Han Dynasty in China, when the emperor could exist, because the power was held by Dong Zhuo and Cao Cao, the emperor was just a fictitious position, but dispensable, when Cao Cao was not ready to become king, he would ostensibly obey the emperor's management, but when Cao Cao was ready to become king, the imperial family could only wait for death.
Similarly, Puyi's puppet Manchurian regime, although ostensibly in charge of power, in fact they did not even have the ability to dispatch troops.
Another way to solve this problem is now the common way of various countries, the government is in charge of the country rather than individuals or families, the existence of the government at least creates equality for everyone in a broad sense, and the power of the state is controlled by elections and other ways, so that under such a system, the country can not only develop smoothly, but also effectively face enemies from all directions.
China's ancient dynasties have not exceeded 300 years, completely in line with the trend of historical development, the world is bound to be divided for a long time, how long a dynasty can persist, and the current rulers have a lot to do with each other, in fact, every emperor will encounter various problems, depending on whether there is the ability to deal with it.
For example, during the reign of Kangxi, there were foreign enemies Gardan, the Southern Ming Dynasty, the internal troubles Wu Sangui and the civil forces Zhu Sanzi, in other time periods, any one of these forces may completely overthrow the dynasty, but Kangxi tried to turn the tide and defeat these forces one by one.
However, in the late Qing Dynasty, the overall situation has undergone a great reversal, the foreign enemy has become more powerful, and the Qing Dynasty has become more and more serious, and the internal troubles have become more and more serious, and the voices of civil resistance have become more and more intense.
In the long river of history, there have been countless excellent families and rulers, but everyone's life is limited, they can claim the king and hegemony in their own time, but they cannot guarantee that their dynasty will always be strong, Qin Shi Huang once had such a beautiful dream, hoping that the dynasty he founded can be passed on forever.
But it turns out that his idea is still too naïve, the dynasty he founded, but it only persisted until the second generation and disappeared, while Liu Bang, who had no culture, established the Han Dynasty that had been passed down for many years, and some things were not something that could be done if he wanted to.