As a basic condition of life activities, the body is warmed and nourished by Yang Qi, maintains normal physiological functions. It can cause blood vessels to become astringent and the skin to lose its nutrition when Yang Qi is insufficient. Professor LI Shi-mao believes that the ulcer of Yang Qi deficiency and cold pathogenesis coagulation is located in the oral cavity, and the critical pathogenic factor is kidney yang deficiency. That is divided into spleen and kidney yang deficiency syndrome and deficiency of fire syndrome (true cold false heat syndrome) . Professor Li emphasizes that kidney yang deficiency is an important factor in the formation of oral ulcer. Moreover, he strongly convinced that diagnosis of oral ulcers should be based on the pulse, so as to Initially distinguish between false syndrome and positive syndrome; Finally, we could perform specific treatment is based on syndrome differentiation according to pulse diagnosis and its characteristics.Specially, the warm kidney viscera and urgently supplement Yang Qi is established as an important treatment principle for oral ulcers by TCM. Professor Li proposed to treat the spleen and kidney yang deficiency syndrome of oral ulcer with the method of increase Yang Qi moderately and eliminate cold pathogenesis, and could make good use of wind medicine and fried charcoal into medicine; with the method of Warming and smoothing meridians and blood vessels to treat the syndrome of feeble Yang Qi and severe stagnation of cold pathogenesis lead to oral ulcer, and pay attention to inspiring to Yang Qi and invigorating the body; with the method of warming the latent and lowering the fire to treat oral ulcer of the syndrome of flaring up of deficient fire, and could appropriate add Longmu and Cornus to reduce the floating fire. All in all, using the method of warm supplement Yang Qi treats oral ulcers could promote the recovery of Yang Qi of body, dissolve and eliminate the coagulation of cold pathogenesis, restrain deficient fire, and achieve the healing of oral ulcers.