OBJECTIVE To determine the effect of basic fibroblast growth factor (bFGF) on the biological behaviour of ovarian epithelial neoplasm. METHODS Ten cases of normal ovarian tissues and eighty cases of ovarian epithelial tumor tissues were detected by immunohistochemical methods. Mias-2000 Picture Analysis System was used to study the relationship of bFGF expression intensity and microvessel count, FIGO stage, pathological grade and classification of ovarian epithelial neoplasm. RESULTS 1. Expression of bFGF was mainly in cytoplasm and nucleus in several cells of borderline and malignant tumor. 2. The expression intensity of bFGF was closely related to the malignant degree of ovarian epithelial neoplasm. The density of bFGF expression was (3.35 +/- 3.52)% in normal ovarian epithelium, (19.25 +/- 21.73)% in benign tumor, (33.78 +/- 10.86)% in borderline tumor and (48.18 +/- 12.93)% in malignant tumor. The results indicated that bFGF might play an important role in carcinogenesis of ovarian epithelial neoplasm. 3. The expression intensity of bFGF was increased with the FIGO stage of ovarian tumor. 4. The expression intensity of bFGF was increased accompanying with the decrease of differentiation degree in ovian neoplasm. 5. In borderline tumor, expression intensity of bFGF in serous cystadenoma was significantly higher than in mucinous cystadenoma, which indicated bFGF might be an important factor in canceration of ovarian epithelial neoplasm. CONCLUSION bFGF may play important roles in carcinogenesis, development, invasion and metastasis of ovarian epithelial neoplasm.