Sun Zongwei was born in Changshu, Jiangsu province. He passed the entrance exam and entered the Department of Arts of National Central University in 1934. In 1938, he joined the group of war sketch in his department and headed to the front of the Fifth War Zone where they promoted, through painting, the spirit of resistance against Japanese invasion. He graduated in the same year and stayed on to serve as a teaching assistant in his department. In 1941, on the recommendation of Lv Sibai, the dean of the Department of Arts of National Central University, he became an assistant to Zhang Daqian, whom he accompanied to Mogao Grottoes, Yulin Grottoes, Western Thousand Buddha Caves, and Tar Lamasery, where they copied and researched on the grottoes.During this period, Sun produced a large number of sketches and oil paintings of the Mongolian and Tibetan people. In 1942, he returned and continued his teaching in the Department of Arts. He was also employed by Xu Beihong and served as associate researcher at the China Art Academy. From 1946 to 1949, he was an associate professor at National Beiping Art College and joined the Beiping Artist Association. After the establishment of the People’s Republic of China, Sun worked as an associate professor in the Department of Painting at the China Central Academy of Fine Arts and professor at the Department of Stage Art of the Central Academy of Drama.