Abstract: Objective: To investigate the expression of vascular endothelial growth factor (YEGF) and microvascular density (MYD) in serous ovarian tumors and their role in the progression of the tumor. Methods: Measuring the expression of YEGF and MYD by routine s-p immunohistochemistry in 19 serous ovarian cystoadenocarcinomas, 15 borderline serous ovarian cystoadenomas and 13 serous ovarian cystoadenomas. Results: The expression of YEGF and MYD in serous ovarian cystoadenocarcinomas (29.50±7.54 and 25.16,8.44) are significantly higher than those in borderline serous ovarian cystoadenomas (11.64±2.07 , 8.54±3.68) and serous ovarian cystoadenomas (1.55±1.23,1.88±0.85), P=0.000 for both; The expression of YEGF and MYD in borderline serous ovarian cystoadenomas are significantly higher than those in serous ovarian cystoadenomas, P=0.006 and P=0.000 respectively; The expression of YEGF and MYD in serous ovarian cystoadenocarcinomas grade Ⅲ(34.59±2.13 and 30.99±9.59) are significantly higher than those in carcinomas grade Ⅰ~Ⅱ (26.53±7.04 and 21.76±6.60),P=0.020 and P=0.023 respectively; 8-year follow-up results showed that the expression of YEGF in the carcinoma tissue of living cases is significantly lower than that of the died cases, MYD did not show such significance; Correlation analysis showed that there was a positive correlation between the expression of YEGF and MYD (P=0.000). Conclusions: Our findings in this study indicate that the higher expression of YEGF and MYD in serous ovarian cystoadenocarcinomas and borderline serous ovarian cystoadenomas may play a role in the progression of serous ovarian tumors. YEGF and MYD may be a prospective auxiliary marks of evaluation of the prognosis due to their higher expressions in higher grade, although no relationship was found between the stage of carcinoma and their expression.