OBJECTIVE： To establish psoriasis animal model with a longer duration and more typical psoriatic characteristics by modifying psoriasis model induced by imiquimod. METHODS： Mice were randomly divided into normal group （treated with vaseline）， model group [treated with Imiquimod cream 60 mg/（2×3 cm2·d）] and modified group [treated with Imiquimod cream 60 mg/（2×3 cm2·d）+subcutaneous injection of rmIL-12 and LPS once a week]， for consecutive 21 d， with 10 mice in each group. The skin of the model site was observed daily from the first day of modeling. Psoriasis area and severity index （PASI） score was conducted for skin lesions such as erythema， scales and thickening. 21 d after modeling， mice were sacrificed， and histopathological examination of the skin lesions was performed. The spleen index was calculated， and the contents of IL-17A and IL-12 in the skin were detected by ELISA. RESULTS： From the third and second day of medication， erythema， scales and thickening were both observed in model group and modified group respectively. The PASI score reached peak on the 12th day. From the 11th day， erythema， scales and thickening of the modified group were more serious than that in model group. PASI scores of modified group was significantly higher than that of model group for 9 consecutive days （P＜0.05）. Histopathological observation showed that Munro microabscess， acanthosis and dermal inflammatory cell infiltration occurred in both model group and modified group. Compared with model group， spleen indexes of modified group were higher （P＜0.05）. Compared with normal group， the contents of IL-17A and IL-12 in mice skin of model group and modified group were both increased， and there was statistical significance in modified group （P＜0.05）. CONCLUSIONS： The estbalished modified model has the longer duration of typical characteristics of psoriasis.