Abstract: Objective To investigate the expression of vascular endothelial growth factor (VEQF) in human placental trophoblasts and the role of VEGF in regulating placental villous angiogenesis. Methods Placental samples were obtained from 10 pregnant women receiving induced abortion in the first trimester, 10 receiving induced labor in the second trimester and 10 having cesarean section at term delivery, with gestational duration of 6-9, 18-22 and 37-38 weeks, respectively. All the samples were fixed in formalin solution and prepared for the morphological study. The expression of VEGF and vascular distribution in the placental villi were examined and evaluated by immunohistochemistry and stereomorphometry, respectively. Results In the course of pregnancy, there was a significant decrease in the level of VEGF expression in chorionic villi (28.19±3.01, 18.65±2.43, 4.95±0.86, respectively, P<0.01). The radial parameters of the blood vessels showed no significant changes (26.67±7.74, 25.08±4.67, 23.36±5.30, respectively, P>0.05), but the length density of the blood vessels increased significantly (1.46±0.64, 5.58±1.31, 19.56±1.40, respectively, P<0.01). Conclusion During gestation, VEGF expression in chorionic villi gradually weakens but the length density of the blood vessels increases, indicating that VEGF is not the only regulatory factor of angiogenesis in the chorionic villi.