Abstract: The effect of lunar phase of earthquakes with M_L≥4.0 occurred in North China since 1970 is analyzed. The results indicate that the occurrence of earthquakes with M_s≥5.0 does not show correlation with the lunar phase and is obviously stochastic. Before the strong earthquakes with M_s≥7.0, however, the occurrence of the moderate earthquake is obviously related to the lunar phase. It is significant in the medium-and short-term prediction of earthquakes M_s≥7.0. When the moderate earthquakes occur near the period of new moon or full moon, the future strong earthquakes would occur. At Present, the occurrence of the moderate earthquakes in North China does not show correlation to the lunar phase, so thepossibility of the occurrence of earthquakes with M_s≥7.0 will be relatively low.

Key words: North China, Seismicity, Effect of lunar phase