In 1928, Wu Huawen became Head of Training Department, Luoyang Junior Military Officer School of the North-western Army.

[1] After that came appointments as Chief of Staff and commanding officer of the Reconnaissance Regiment in the 25th Division of the 2nd Army Group (1928–1930),[1] Deputy Head of the Higher Training Corps of the 3rd Route Army (1930–1931),[1] commanding officer of the pistol brigade, 3rd Route Army (1931–1938),[1] commanding officer of the 28th Independent Brigade, 3rd Route Army (1938–1939),[1] and general officer commanding the 4th New Division (1939–1943).

[2] In the same year, he joined the Reorganized National Government of China,[1] a puppet state under Japanese control.

Before the beginning of the battle, Wu Huawen defected to the Communist side taking a large number of troops with him and hence delivering a decisive blow to the Kuomintang defense of the city.

During the Yangtze River Crossing campaign, he was instrumental in the capture of Nanjing.