Objective: To investigate and establish the reference range of embryonic/fetal heart rate(EHR) during early pregnancy that in accordance with the characteristics of Shanghai population. Methods: The EHR, the clinical history and laboratory examination of pregnant women and embryos were collected. Embryonic / Crown-rump length(CRL) and the heartbeat was detected by transvaginal and/or transabdominal ultrasound. Embryonic/fetal heart beat was measured by M type ultrasound or pulse Doppler (pulse wave, PW). Results: 1. When CRL was 2-3mm or gestational age (GA) was 40-41 days, the fetal heart rate was 117.31 + 11.64 beat/min (beats per minute, bpm). Then EHR raised with the increase of GA/CRL, and at the 63-69 day of the gestational age when the embryo length was 23~30mm, the heart rate reached thr peak of 172.69 ±9.27 bpm. After that, the EHR gradually decreased and tend to stable with the GA or CRL. 2. The regression equation was established through the changes of EHR in each period: EHR（bpm）=-223.751+11.746GA（day）-0.086GA^2 （day）（R^2=0.772，R=0.877，P<0.0001）；EHR（bpm）=101.83+5.108CRL（mm）-0.084CRL^2 （mm）（R^2=0.765，R=0.875，P<0.0001）. Conclusion: Based on the gestational age and length of GA/CRL, the regression equation was established, and the 5th, 50th and 95th percentile of HER in Shanghai area, which was helpful to clinical diagnosis and treatment.