Abstract: For earthquakes of M_S≥8.0 that occurred around the world and earthquakes of M_S≥7.0 that occurred in mainland China from 1963 to 2017, we investigated the correlation between the seasonal variation of Earth’s rotation and the occurrence of earthquakes via the phase angle with a statistical test. The obtained results are that for earthquakes of M_S≥7.0 that occurred in mainland China, approximately 81 percent of those occur during both the beginning of the acceleration of the seasonal variation of Earth’s rotation and the period from the around peak point to the beginning of the deceleration with a significant correlation （α=0.001）. For earthquakes of M_S≥8.0 that occurred around the world, approximately 68 percent of those occur during the period around valley point with a significant correlation （α=0.001）.