In the twenty-fourth year of Jian'an (219), Guan Yu attacked Fancheng in the north, and when the war was critical, he asked Liu Feng and Meng Da, who were stationed in Shangyong, for help, but Meng Da urged Liu Feng not to send troops to aid Guan Yu, resulting in Guan Yu fighting alone and being defeated and killed.
Afterwards, Liu Bei pursued the blame, meng Da could not escape the blame, and falsely left a letter to Liu Bei, leading his subordinates to surrender to Cao Wei and run away, while Liu Feng was not spared and was forced to commit suicide.
After Meng Da surrendered to Cao Wei, the Wei Emperor Cao Pi, because of Meng Da's talents and good looks, liked Meng Da very much, reused it, and appointed Meng Da as a regular attendant on horseback, accompanying him, and Meng Da was like a fish, and was favored and treated favorably.
However, not long after the good days, Cao Pi fell ill and died, and Meng Da lost his patron, because he had been treated favorably by Cao Pi before, and many people were jealous of Meng Da, and Meng Da felt that it was very dangerous in Cao Wei and could not stay.
Just at this time, Zhuge Liang's Northern Expedition learned of Meng Da's situation, so Zhuge Liang wrote to Meng Da and took the opportunity to win over, Meng Da saw Zhuge Liang throw out an olive branch, the meaning was so clear, so, as soon as he hit it off, he immediately replied to Zhuge Liang, willing to raise troops in response to Zhuge Liang's military actions and defected to Shu Han.
Meng Da responded to Zhuge Liang, this is a rebellion, coupled with Meng Da's unclassified work, the information was quickly leaked out, Sima Yi learned of the situation, immediately decided, and led troops to attack Meng Da.
At this time, someone reminded Meng Da not to be careless, and Zhuge Liang also wrote a letter to advise Meng Da to be careful, but Meng Da did not care, Meng Da wrote back to Zhuge Liang, saying that Wancheng was eight hundred miles away from Luoyang, farther away from me, there were twelve hundred miles, even if Sima Yi knew that I was rebelling, he gave it to Tianzi, and it would take at least a month to go back and forth, at that time, I had already repaired the city and made sufficient preparations, and Sima Yi could not help me.
Zhuge Liang learned that Meng Da was so careless, unguarded, angry and stomped his feet, almost vomiting blood, but there was no way, Meng Da wanted to die, no one could save him.
When Sima Yi learned of Meng Da's move, he immediately led his troops to suppress the rebellion, marched day and night, and in just eight days he was under the city, and Meng Da was also shocked when he saw Sima Yi's army arrive, which was indeed unexpected by him, but it was already late at this time.
Meng Da wrote another letter to Zhuge Liang, saying, I want to raise a matter, Sima Yi will come to the city in eight days, how fast!
At this point, Zhuge Liang had no way to save Meng Da.
Meng Da set up a wooden fence outside the city to block Sima Yi's army, but it was a mantis arm to block the car, and it could not be stopped at all, and Sima Yi waved his army to cross the water, destroyed its wooden fence, and attacked fiercely.
In the first month of the second year of Taihe (228), Sima Yi's troops divided into eight roads and attacked the city together, and in only sixteen days, Meng Da was finished, because the castle was often broken from the inside first.
At this time, Meng Da's army also had traitors, and Meng Da's nephew Deng Xian and his general Li Fu Kaesong surrendered to Sima Yi. Immediately, Sima Yi's army entered the city, beheaded Meng Da, and passed on the capital to the capital division.
The capricious Meng Da, where is Sima Yi's opponent, Meng Da finally killed himself.