Following the defeat of the Guominjun in the Anti–Fengtian War Feng Yuxiang participated in the Northern Expedition, Sòng assumed the Chairmanship of Shaanxi province in November 1927 and in April of the same year the head of 4th division under the II Corps of the National Revolutionary Army.

Though poorly equipped compared to the better armed Japanese, Song led the 29th army to resist the aggression in a war known as the Defense of the Great Wall (熱河長城之戰).

However Han Fuqu, chairman of the province and suspected for his clandestine Japanese liaison, forbade Song to retreat across the Yellow River, resulting in the 29th Army being shattered at Shijiazhuang in December 1937 and January 1938.

Remaining forces suffered various losses against the Imperial Japanese Army and were delegated to guerrilla combat after retreating into the mountainous regions at the borders of Henan and Shanxi province in February 1938.

He soon suffered various illnesses and died at the age of 54 in Mianyang County, Sichuan province after several unsuccessful medical treatments in Guilin, Chongqing, and Chengdu.