This paper introduces Yang Wei’s clinical experience in the treatment of anal fistula of Crohn’s disease with combination of Chinese and western medicine. It is considered that the pathogenesis is downward flow of damp-heat as the branch cause, and qi deficiency of the spleen and stomach as well as qi and blood deficiency of the liver and kidney as the root cause. In the treatment, Professor Yang advocates the combination of Chinese and western medicine, disease differentiation and syndrome differentiation, and the combination of medication and surgical treatment. She selects the timing of operation, pay attention to the protection of anal function, striving for fistula healing through staged operation and thorough drainage. And one proven case is presented.