After the end of the First United Front which result in the split between the Communist and the Kuomintang, Zuo travelled to Moscow where he studied at Sun Yatsen University and then the Soviet Military Academy, graduating in 1930.

Zuo travelled back to China, arriving in Shanghai with Liu Bocheng, and was sent to the Soviet area in Jiangxi.

In 1941, when the Social Affairs Department (Shehuibu) sent an intelligence detachment to the Eighth Route Army to support it, that group was at first sponsored by Zuo Quan who subordinated it to his own staff within a year and subsequently controlled its tasking, personnel, and operations.

While under Zuo the detachment successfully established intelligence stations behind enemy lines throughout the Taihang-Shandong area, and set up an agent network in Beiping.

In May–June 1942 Zuo engaged in battles to cover the retreat of the Eighth Route Army, and was fatally wounded by a Japanese artillery shell on 2 June 1942 while leading a breakout.