Pai-wen Sun began his career as a captain under the 9th Imperial Army Corps. Then he joined the First Revolution and took part in the capture of Nanking. He was connected with the Ministry of War in the Nanking Provisional Government.
In 1920 Mr. Sun went to Canton to re-join the Revolutionary Party. He later became chief of the faculty administration bureau of the Whampoa Military Academy. During the Northern Expedition, he held the post as chief of the Headquarters, transportation section Garrison Commissioner of the Hsuchow and Haichow districts in Kiangsu in 1927. In 1928, he was Garrison Commissioner of the Kiangning Strategical Area.