Psoriatic arthritis is a refractory immune-related disease belonging to the category of "BaiBi" or "BiZheng" in Chinese medicine. Modern Chinese medicine scholars describe it as "BiBi". Traditional Chinese medicine (TCM) has good efficacy in the treatment of "BiBi", it is generally believed that the cause of BiBi is mainly attributed to "wind evil and blood dryness". But the understanding of BiBi is mostly on "heat damage to Yin essence", and there is insufficient understanding of Yang deficiency. The author tries to analyze BiBi from the axis of "Yingwei-Xuanfu", and consider that the lack of Yang, the loss of Qi and blood, and the disharmony between Yingwei are the initiation of the disease, and that the key to the pathogenesis of psoriatic arthritis is the invasion of evils, stagnation of evils in the Xuanfu and Qi, blood stasis. The idea of recognizing and treating the disease by strengthening Yang is proposed in order to provide a new method for the treatment of psoriatic arthritis.