Psoriasis is a chronic inflammatory skin disease with multiple layers of silvery white scales on the surface of erythema papule as the main clinical characteristics, of which yang-deficiency external cold psoriasis is refractory, recurrent and severe in winter and mild in summer, which has a great impact on patients\' physical and mental health and quality of life. Traditional Chinese medicine has unique insights in the treatment of psoriasis, both curative effect and safety, have obvious advantages. Based on the concept of “winter disease and summer treatment”, long-snake moxibustion gives full play to its functions of warming the kidney, invigorating the marrow, warming the meridians, activating blood circulation and removing blood stasis, so as to restore the deficiency of Yang in patients with psoriasis with external cold syndrome, enhance disease resistance, and prevent psoriasis recurrence or aggravation in winter. Therefore, based on the theory of “winter disease and summer treatment”, this paper preliminarily discusses the mechanism of long-snake moxibustion in the prevention and treatment of psoriasis with external cold syndrome of Yang deficiency, and provides new ideas and directions for the prevention and treatment of psoriasis with traditional Chinese medicine.