Abstract: CPC’s proposal of four guarantees for Kuomintang’s third plenary telegraph was originated from the two letters that was telegraphed by the communist international executive committee secretariat to the central committee of the communist party on January 20 and February 5 of 1937. On July 15, “The Declaration of Cooperation between KMT and CPC” was submitted, and the modified four guarantees in this declaration fully absorbed the spirit of the letter telegraphed by the communist international executive committee secretariat to the central committee of the communist party on February 5. The content of the previous negotiations of KMT and CPC in Xian, Hang Zhou and Lu Shan involved the issues of the communist party and the army under the leadership of CPC, the local government and each party’s united front, etc. but the main focus was about the legitimacy of the communist party. Chiang Kai-shek adopted relatively loose strategy in negotiations for the red army and the Soviet government, the main purpose of this was to dissolve the communist party and force communist give up independence. He tried his best to lay aside the “China’s communist manifesto on Kuomintang-Chinese communist cooperation” in order to delay the legalization of the communist party as far as possible. Under the resolute insistence of CPC and the persecution of Japanese military’s offensive attack, Chiang Kai-shek, firstly, orally admitted the legal status of Shan Ganning border region, then agreed to the adaptation of Red Army, and finally was forced to publish the “China’s communist manifesto on Kuomintang-Chinese communist cooperation”. It tells us, from the opposite way, the utmost importance of CPC during the new-democratic revolution stage.

Key words: CPC, KMT, Lu Shan Negotiation