Objective To Investigate whether the PDEs activities is abnormal or not in psoriasis patients by detecting the PDEs activities of both psoriasis patients and healthy controls, and explore the potential role of PDEs activities changes in the pathogenesis of psoriasis. Methods PDEs activities were detected by using high performance liquid chromatography(HPLC) in 50 patients with psoriasis and 60 healthy controls. Results The PDEs activities is 10.40%±3.54% in psoriasis patients,and 8.60%±2.25% in the healthy controls. The PDEs activities in patients with psoriasis is significant higher than that in the controls (P0.05). Conclusions The PDEs activities may be a risk factor for psoriasis.