To investigate the effect of Erzhi Tiangui keli, a kidney tonic, on theca folliculi and endometrial blood flow in patients undergoing controlled ovarian hyper-stimulation (COS).Methods:Sixty-six patients with infertility of tubal factors who are undergoing IVF-ET were divided into two groups at random: 33 cases given COS treatment alone, 33 cases treated by COS plus the abovementioned keli. Theca folliculi and endometrial blood flow were detected by TV-CDFI on the day of HCG administration to analyze correlation. Results:There was no correlation between theca folliculi and endometrial blood flow (P>0.05). Theca folliculi RI and endometrium PI 、RI were significantly lower in treat group than in control group (P<0.01,0.01,0.05,).Conclusion:Erzhi Tiangui keli can enhance the quality of oocyte and endometrial receptivity by improving theca folliculi and endometrium perfusion.