OBJECTIVE： To observe therapeutic efficacy and safety of modified Longdan xiegan tang in the treatment of psoriasis vulgaris （blood heat type）. METHODS： A total of 80 patients with psoriasis vulgaris （blood heat type） were randomly divided into control group （38 cases） and observation group （42 cases），other 30 healthy volunteers were included in healthy control group. Control group was given Xiaoyin tablet 1.6 g orally， 3 times a day for 4 weeks. Observation group was given modified Longdan xiegan tang， 400 mL after detected with water， 1 h after breakfast and supper， 7 d as a treatment course， for 4 courses. Clinical efficacies and PASI score were observed before and after treatment. The levels of inflammatory factors （IL-1， IL-6， IL-8， TNF-α）， the expression of NF-κB protein and NF-κB gene were observed in observation group before and after treatment， and then were compared with healthy control group. The relationship of inflammatory factor levels with NF-κB protein expression in observation group before treatment， the relationship of PASI score with inflammatory factor and NF-κB expression were observed in observation group before and after treatment， and the occurrence of ADR was recorded. RESULTS： Total response rate of observation group （85.7％） was significantly higher than that of control group （52.6％）， with statistical significance （P＜0.05）. Before treatment， there was no statistical significance in PASI score between 2 groups （P＞0.05）. After treatment， PASI score of 2 groups were significantly lower than before treatment， and the observation group was significantly lower than the control group， with statistical significance （P＜0.05）. After treatment， The levels of IL-1， IL-6， IL-8 and TNF-α in observation group were significantly lower than before treatment， but there was no statistical significance with healthy control group（P＞0.05）； the expression of NF-κB protein and NF-κB gene in observation group were significantly higher than healthy control group， with statistical significance （P＜0.01 or P＜0.05）. The levels of IL-1， IL-6， IL-8 and TNF-α were positively associated with the expression of NF-κB protein in observation group before treatment. The levels of IL-1， IL-6， IL-8 and TNF-α and the expression of NF-κB protein were both positively associated with PASI score in observation group before and after treatment. CONCLUSIONS： Modified Longdan xiegan tang show significant therapeutic efficacy for  psoriasis vulgaris （blood heat type）， can reduce PASI score， the levels of NF-κB protein expression and inflammatory factors.