聯俄容共
In 1925, Chen enrolled at Shanghai Labor University, studying literature, and in 1927 he joined the Communist Party of China. After returning to Fujian, he was hired as the personal secretary of General Zhang Zhen, helping to prepare for the 1926–1927 Northern Expedition from the CPC side of the First United Front. When the Front collapsed, Chen fled and was eventually arrested in Nanjing. He was released after a month on General Zhang's recommendation. Shortly thereafter, Chen was sent by the Party to Moscow Sun Yat-sen University, where he studied politics and Marxist philosophy for four years.