The results of 296 endoscopic sinus surgery (ESS) from Oct. 1991 to May, 1993 were analysed. Pre- and post-operative examinations in this series were as follows: 1. Peripheral blood T lymphocyte subclusters test (100 cases): 2. Immunohistochemical test of nasal polyp (103 cases): 3. Pathologic examination of nasal polyp: 4. CT scan typing (103 cases). Men and women ratio was 2:1 and their ages varied from 7 to 72 years. 107 patients were given general anesthesia and 189 patients local anesthesia. The clinical stages of chronic sinusitis were divided as: 53.7% (N), 29.3% (II), 10.9% (III) and 6.1% (I). The clinical curative rate was 85.7% (126/147 cases), and improving rate was 99.3%. The standard of clinical stage of chronic sinusitis, the relative factors of prognosis with the results of ESS, pathological test, immunohistochemical test and follow-up after ESS were discussed.