Earthquake and mud-rock folw are all the common natural disasters. This paper preliminarily discusses the effects of earthquake on formation of debris folw and some features of induced earthquake debris flows. It is considered that the regions where seismicity is strong or neotectonic movement is active are usually the regions where debris flows frequently occur; earthquakes affect the formation and development of debris flow by nourishing loose solid material, water source, dynamic and triggering condition; debris flows induced by seismic activities often have overdue, periodic and regional characters.