The analysis of Heart Rate Variability (HRV), as a noninvasive method in detecting function hearts has been applied widely and is a hot spot for ECG signal processing for its capability to assess function of autonomic nervous system and intrinsic dynamic mechanism of heart quantitatively, and to explain and predict the heart movements. In the present, the method of analysis of HRV signal mainly lies in linear analysis and nonlinear analysis. Research progress of several methods of HRV analysis is presented. And expectation is presented to the analysis of HRV signal and its application in the field of space medicine in the future.