In this paper, M ≥ 7.0 earthquakes occurred in the world during the period of 1900 to 2011.6, namely, six 18.6 year cycles, are selected. According to plate tectonics, these earthquakes are divided into 13 research region, and their relationship with the lunar declination angle is analyzed. The research results show that any seismic activity period of each research region corresponds to a certain interval of lunar declination angle. These provide a scientific basis for the future mid-to-long-term earthquake trend prediction in each research region. It is worth further study.