The measurement of Heart rate variability (HRV) is a widely used and non-invasive method to assess the status of autonomic nervous system (ANS) and circulatory system. We try to And out the relation between two aspects: R-R intervals analysis on time domain (SDNN, RMSSD) and frequency domain (low and high frequency components), which shows the correlations between autonomic nervous system (ANS) and circulatory system. A resting stage (as the baseline) is often introduced before the experiment stimulus. There were thirtytwo young healthy male subjects in our experiments. We found that in a normal rest, both people's autonomic nervous system and circulatory system will calm down after ten minutes. The calm status can last for at least nine minutes. This statement is based on a statistical analysis in the intervals of participants' heartbeats. We have the conclusion as follows. There is a significant correlation between autonomic nervous system and circulation system. And when resting, one's circulation system will become slower while one's autonomic nervous systemparasympathetic and sympathetic nervous system both become more active. Before a psychophysiological experiment designed, ten-minute resting time is suggested to make sure the participants are calmed down.