Wu Hao incident is an unexpected episode in the history of the Communist Party of China and a crisis in Zhou Enlai's political life. The whole incident is caused by Gu Shunzhang's "betrayal", leading to the arrest of a large number of Communists. Zhang Chong who was then the Director-General of the Investigation Section of the Central Organization Department of the Kuomintang (Nationalist Party of China), learned the information that Wu Hao was a pseudonym of Zhou Enlai from confessions of those Communists "turning themselves in and turning over a new leaf". To damage the loyalty of the Communist, Zhang Chong created the false appearance of Zhou Enlai leaving the Party to break up the Communist Party. How did Zhou Enlai deal with the crisis in the face of the threat from the Kuomintang? How was the Special Operations Section of the Communist Party of China rebuilt to punish "traitors"? Actually, the whole incident didn't have much effect at that time but caused a political storm decades later. So, how did Zhou Enlai defend his integrity in his later years? All of these problems above are mainly discussed in this paper.