Some investigators state that the development of follicle is related with the autonomic nervous system (ANS), but Traditional Chinese Medicine (TCM) believes that liver governing free coursing affects the conversion of yin and yang into each other in the period of ovulation. Moreover, the function of liver is related with autonomic nerve system in tradition Chinese medicine. In this study, we investigated the relationship between ovulation and autonomic nervous system through heart rate variability (HRV) analysis in healthy women. The HRV index (the SDANN and the ratio of LF/HF) of 35 healthy women was detected on the 9th, 14th, and 19th day of menstrual cycle. In these women, the SDANN is significantly increased and the ratio of LF/HF is significantly decreased on the period of ovulation (the 14th day of menstrual cycle). It suggested that autonomic nerve system may play an important role in menstrual cycle, especially in the induction of ovulation.