This article uses the literature research method to explore Qu Yuan's diplomatic advocacy of "harmony with Qi and resistance to Qin", starting from Zhang Yi's mission to Chu in 311 BC to lobby for "reconciliation between Qin and Chu", the marriage between Qin and Chu in 305 BC, and 304 BC The Qin-Chu Alliance, the Qin-Chu Alliance in 299 BC, and the Qin-Chu Alliance in 293 BC, Qu Yuan opposed and was exiled to a remote area in the south. Why did Qu Yuan's "alchemy with Qi against Qin" fail, and the "Qin-Chu marriage" between King Huai of Chu and King Qingxiang of Chu also failed to save Chu from being destroyed by Qin? The study found that Qin had the ambition to annex other countries, and any policy that showed favor to Qin would fail; the only reliable policy was for all countries to unite and jointly resist Qin's aggression. However, all countries were short-sighted and only wanted to win over Qin in order to protect themselves, but they were defeated by Qin one by one.