To provide a basis for probabilistic seismic hazard analysis, this paper investigates the correlation between elastic input energy and other intensity measures of ground motions and the difference between offshore and onshore ground motions. A total of 271 earthquake events were collected from the K-NET of Japan, and 1 784 offshore ground motion records and 4 480 onshore ground motion records were selected. Seven representative intensity measures were determined through correlation analysis. Firstly, the correlation between the selected intensity measures and absolute and relative input energy under different epicentral distances was calculated, and the results were analyzed from the perspectives of period and epicentral distance. Secondly, the correlation between intensity measures and absolute and relative input energy under different damping ratios was analyzed. Finally, the difference in the correlation between offshore and onshore intensity measures and input energy was compared. Results show that the intensity measures that have the best correlation with the input energy of offshore and onshore ground motions are mostly the same in different periods, but there are differences in the extreme values of the correlation coefficient between the intensity measures and the input energy for offshore and onshore ground motions under different epicentral distances. Under different damping ratios, the correlation between the same intensity measures and input energy are different between offshore and onshore ground motions. Through preliminarily analysis, it was found that the difference might be caused by the rich low-frequency components of offshore ground motion. Therefore, the influence of damping ratio and epicenter distance should be considered when studying the correlation between input energy and intensity measures. The results can provide reference for the related research of offshore and onshore probabilistic seismic hazard analysis engineering.