Objective To explore the changes of serum vascular endothelial growth factor ( VEGF) and endostatin (ES) in patients with polycystic ovary syndrome (PCOS) and their effects on the ovarian stromal blood flow. Methods From January 2015 to January 2017,sixty cases diagnosed with polycystic ovary syndrome in the Eighth Affiliated Hospital of Sun Yat?sen University were selected into the observation group,and other 60 cases of healthy women with normal menstrual cycle in the same period were selected as the control group. Then, the levels of serum VEGF and ES of the two groups were observed, the patients in the early ovarian follicular blood flow changes were monitored by transvaginal color Doppler ultrasound to observe the bilateral ovaries and the hemodynamic indexes. Hemodynamic indexes (pulsatility index and resistance index) were compared,and the effects of serum VEGF and endostatin levels on ovarian interstitial blood flow were analyzed. Results The PI and RI of the observation group were(1. 3±0. 2) and (0. 5±0. 1),the PI and RI of the control group were (2. 4±0. 4)and(1. 0±0. 1),the differences were statistically significant(t=2. 378,2. 578,P=0. 023,0. 014);the levels of VEGF and ES in the observation group were (1083±167)ng/L and (278±23)ng/L,the levels of VEGF and ES in the control group were (625±71) ng/L and (172±21)ng/L,the differences were statistically significant( t=2. 123,2. 892,P=0. 042,0. 008);there was negative correlation among VEGF and PI and RI ( r=-0. 770,-0. 782,P<0. 01);there was negative correlation among ES and PI and RI ( r=-0. 751,-0. 799,P<0. 01);there was positive correlation between VEGF and ES ( r=0. 552,P<0. 01) . Conclusion The serum levels of VEGF and ES are significantly increase in patients with polycystic ovary syndrome, the imbalance between the two expressions may play an important role in the increase of ovarian stromal blood flow.