To study the histogenesis, biological behaviour, classification of pituitary adenoma and the relationship between the symptoms of hormonal hypersecretion and the hormone test in pituitary adenoma. MethodsOne hundred and eighty cases of pituitary adenoma were investigated by clinicopatholgic analysis, and GH, PRL, ACTH, TSH, FSH, LH were examined in 110 cases by ABC immunocytochemical methods. ResultsForty percent of the patients were found to have the identical results between the clinical symptoms and hormonal test. Female patients were more than male ones, and the difference was satistically significant. The results showed that PRL and GH adenoma were often found in the cases by immunocytochemical method,and mixed GH-PRL adenoma were often found in the cases with multihormono-adenoma. ConclusionThe classification is practical and easy to operate, which combines the immunohistochemical examination of pituipary adenoma with the morphology and function.