To observe the clinical efficacy and safety of Diyu Huaihua decoction combinde with methotrexate in treating psoriatic arthritis. Methods:A randomized controlled study was conducted. 51 cases of PSA were randomly divided into two groups， the control group (25 cases) was given methotrexate therapy while the treatment group (26 cases) was given Diyu Huaihua decoction and methotrexate combination treatment for 12 weeks， observed the changes of clinical and laboratory parameters in the two groups of patients before and after treatment. Results:After 12 weeks of treatment， compared with pre-treatment， the VAS score， duration of morning stiffness， swollen joint count， tender joint count， ESR， C-RP and skin lesions PASI score of the two groups showed significant improvement(P<0.05)， and compared with the control group， the differences of these index in treatment group before and after treatment were significant(P<0.05); the incidence of adverse reactions was significantly higher in control group when compared with treatment group (P<0.05). Conclusion:Diyu Huaihua decoction combined with methotrexate combination can significantly improve joint symptoms， relieve skin lesions and has smaller adverse reactions.