This paper introduces national Chinese medical science master Lu Fang’s experience in treating autoimmunity skin lesions with Yimian Decoction. It is considered that the pathogenesis of this disease is disharmony of Ying and Wei,dry and rotten skin. Yimian Decoction can harmonize yingfen and weifen,clear heat and cool blood,promote fluid production and dissipate masses,remove toxicity and dredge channels. The modified recipes according to symptoms should pay attention to the etiology-based medication and application of channel ushering drug of skin. One proven case is presented.