This paper aims to introduce Professor Cao Yemin’s clinical experience in the treatment of diabetic foot gangrene (tendon gangrene). Professor Cao believes that the main pathogenesis of tendon gangrene is exogenous damp-heat, blood stasis blocking collaterals and deficiency of qi and yin, and he divides the progress of tendon gangrene into acute onset stage and recovery stage. In the acute onset stage, the internal treatment of traditional Chinese medicine (TCM) is mainly to clear away damp-heat, promote diuresis and remove toxin by adopting modified Huanglian Jiedu Decoction plus Yinchenhao Decoction besides the conventional treatment (controlling blood sugar and infection, improving hypoalbuminemia with TCM therapeutic diet) and external treatment of removing decaying tissues along the tendons. In the recovery stage, "nourishing" is the primary therapeutic principle combined with the external treatment of rodent debridement. As for the dual deficiency of qi and yin syndrome, modified Shengmai Decoction plus Liuwei Dihuang Decoction is used to replenish qi and nourish yin; as for the dual deficiency of qi and blood syndrome, modified Bazhen Decoction is used to replenish qi and nourish blood. Two proven cases are presented.