Abstract: The correlation relationship among impact energy index, elastic energy index and the dynamic damage time was analyzed by the data from coal samples tests under uniaxial compression. The research shows that impact energy index and elastic energy index were positive correlation and they accorded with the relationship of logarithm in the lower values, there was a significant negative correlation between the impact energy index and the dynamic damage time and they accorded with power relation when the dynamic damage time was low. In the experiment of the impact tendentious identification, when some index values at a specific interval, it should appropriately increase the number of samples to improve the accuracy of the results. In addition, if a particular index volatility is too large, while another associated indicator with a good stable, the index can be determined according to the fitting results.