Abstract：Objective：To observe the clinical effect of modified Yanghe tang for psoriasis vulgaris. Methods：A total of 120 cases of patients with psoriasis vulgaris were admitted and treated in department of dermatology in the First Affiliated Hospital of Henan University of Science and Technology from December 2015 to December 2018，and were divided into the observation group and the control group， 60 cases in each group. The control group was given narrow- band ultraviolet B (NB- UVB)， and the observation group was additionally given modified Yanghe tang based on the treatment of the control group. Both groups were treated for four weeks. The clinical effect as well as the scores of Psoriasis Area and Severity Index (PASI) and the Chinese medicine syndrome scores before treatment and after two- week and four- week treatment was compared between the two groups. Results：After four-week treatment，the total clinical effective rate was 95.00% in the observation group， significantly higher than that of 81.67% in the control group(P＜0.05). After two- week treatment， the scores of PASI in the two groups were significantly decreased when compared with those before treatment(P＜0.05)，there being no significance in the difference among the groups(P＞0.05)； after four- week treatment， the score of PASI in the observation group was significantly decreased when compared with that after two-week treatment(P＜0.05)，and lower than that in the control group(P＜0.05). After two- week treatment， the Chinese medicine syndrome scores in the two groups were significantly decreased when compared with those before treatment(P＜0.05)，and the score in the observation group was lower than that in the control group(P＜0.05)；after four-week treatment，the Chinese medicine syndrome score in the observation group was significantly decreased when compared with that after two-week treatment(P＜0.05)，and lower than that in the control group(P＜0.05). Conclusion： Modified Yanghe tang in the treatment of psoriasis vulgaris can effectively reduce the severity and area of skin lesions of patients，and improve their clinical symptoms.