Abstract: The results of determination of the autoantibody, Eirculating immunocomplex(CIC) and complement in 91 cases of psoriasis vulgaris were reported. The results showed that antinuclear antibody and thyroid globulin antibody were negative, the positive rate of rheumatoid factor was 9.09% and of CIC was 16.66%. The levels of CH₅₀ was normal and C₃ was decreased. The role of autoantibody and CIC in the pathogenesis of psoriasis was discussed, and the authors suggest that further study oii immuno-patho genesis of psoriasis may be very important both clinically and theoretically.