Abstract: In this paper, the merits and deriierits of Immunolustochemical stain of paraffin section were discussed methodologically in comparison with the immunohistochemical and immunofluorescent stain of frozen section by the investigation on psoriatic and normal skin specimens using monoclonal antikeratin antibody AE3.The result indicates that the immunohisto-chemical stain of paraffin section is as good as frozen section and the indirect immuno-fluorescent stain of frozen seetion. Besides, the paraffin section can be stored longer, and has well preserved histologic structure. There-fore, the immunohistochemical stain of paraffin section is a good method to be recommended.