In 260 BC, Qin sent troops to attack Zhao, and Qi and Chu saved Zhao. The monarch of the state of Qin put forward: "Qi and Chu save Zhao, if they can cooperate closely, they will retreat, otherwise they will attack." Zhao had no food, so he borrowed it from Qi, but Qi disagreed. Zhou Zi, an adviser to the State of Qi, said, "Why don't you promise to borrow grain to make the State of Qin retreat, and Qin Jun won't retreat without borrowing grain, so that the strategy of the State of Qin will be realized and the strategy of Qi and Chu will fail. And Zhao is like a barrier to harmony, just like lips are like teeth. Lips are cold and toothless. Today's death of Zhao is a disaster for tomorrow, and a friendship between Qi and Chu. Besides, saving Zhao is as urgent as holding a leaky jar to save a burnt jar. Saving Zhao is a matter of righteousness and prestige. It is wrong to save the dying country with morality, defeat the powerful Qin Jun with prestige, and care about food without committing to such a major event. " Qi Wang Jian didn't listen. Qin Jun defeated more than 400,000 Zhao troops in the battle of Changping, and then surrounded Handan, the capital of Zhao (now Handan, Hebei). In the 16th year of Qi (249 BC), the mother of Qi Guojun died.
In the 28th year of Qi (237 BC), Qi went to the State of Qin to meet Qin, and Qin hosted a banquet in Xianyang (now Xianyang, Shaanxi) to entertain Qi.
After Wang Jian died, he appointed his uncle Hou Sheng as Prime Minister. Later, Sheng accepted a large number of treasures sent by spies from the State of Qin, and sent many guests to the State of Qin. Qin gave these guests a lot of good words, but when they came back, they all became spies for Qin and said some treacherous words that were in the interests of Qin. Later, Sheng persuaded Jian to give up the United Kingdom's service for Qin State, not to repair the offensive armaments, and not to help the five countries attack Qin State, so that Qin State could destroy the five countries of Korea, Zhao, Wei, Chu and Yan.
In the forty-fourth year of Qi (22 1 BC), Qin destroyed five countries, and Qi and Hou Sheng sent troops to guard the western border of Qi and refused to introduce Qin. Wang Ben, the general of the political faction of the King of Qin, led an army to attack Qi from the south of Yan, and Qin Jun invaded Linzi (now Zibo, Shandong), the capital of Qi. The people of Qi dare not fight against it. Chen Chi, a guest sent by the King of Qin, tricked Qi into surrendering to the State of Qin, who gave him a fief of 500 Li. At this time, Hou Sheng also advised Qi not to resist and led the army to surrender to the State of Qin. Wang Jian of Qi listened to their plan, surrendered to Qin, and Qi perished. The king of Qin put Qi's family in a remote place, lived among lonely pines and cypresses, and did not provide food. Qi finally starved to death.