To evaluate the effect of manual acupuncture on endometrial blood flow parameters by three-dimensional (3D) power Doppler ultrasound in women undergoing in vitro fertilization embryo transfer (IVF-ET).Seventy patients undergoing IVF-ET were equally randomized into traditional or sham acupuncture treatment group for totally 4 days (from the day of oocyte aspiration to the day of embryo transfer) of treatment by random envelope method at the Reproductive Medicine Center and Outpatient Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medicine College, Huazhong University of Science and Technology from January 2013 to December 2015. Patients in the traditional acupuncture group accepted traditional acupuncture methods with manual acupuncture, and Zhongji (CV3), Qihai (CV 6), Sanyinjiao (SP6), Taichong (LR 3), Tianshu (ST 25), Guilai (ST 29) and Zusanli (ST 36) were chosen. Patients at the sham acupuncture group accepted shallow acupuncture methods at 4 non-meridian points at each shoulder and upper arm. Outcome measures included endometrial ultrasonic indices such as vascularization index (VI), flow index (FI) and vascularization flow index (VFI), endometrial thickness and volume, subendometrial VI (sVI), subendometrial FI (sFI), subendometrial VFI (sVFI), implantation rate, clinical pregnancy rate, abortion rate, live birth rate and number of live births.Finally, 34 patients in the traditional acupuncture group and 35 in the sham acupuncture group completed this trial. VI, FI and VFI of the traditional acupuncture group were significantly higher than those in the sham acupuncture group (P<0.05). No significant differences were found in endometrial thickness, endometrial volume, sVI, sFI, sVFI, implantation rate, clinical pregnancy rate, abortion rate, live birth rate and number of live births (P>0.05).Manual acupuncture performed after oocyte aspiration and before transplantation improved the endometrial blood flow parameters VI, RI and VFI in women who underwent IVF-ET, instead of sVI, sFI and sVFI. Therefore, acupuncture might be beneficial in women undergoing IVF-ET by increasing endometrial blood flow and endometrial receptivity. (Registration No. ChiCTR2100053354).© 2023. The Chinese Journal of Integrated Traditional and Western Medicine Press and Springer-Verlag GmbH Germany, part of Springer Nature.