The focal mechanism solutions of the M5. 1 Badong earthquake and subsequent 34 aftershocks at ML2. 0 or more were calculated using the P-wave first motion method; the main earthquake was normal fault dip slip type,and the slip types of the seismogenic rupture surfaces of the subsequent aftershocks primarily include normal dip slip( 14 times),reverse dip slip( 9 times),normal strike slip( 9 times) and reverse strike slip( 2 times). The M5. 1 Badong earthquake activities may be related to the stress adjustment caused by the rise of the groundwater level and the decrease of the frictional resistance between structural planes of rock formations due to the effect of reservoir water penetration,and related to the joint activities of the NE-strike Gaoqiao fault and the near EW-strike Daping fault. The focal mechanism solutions of the M5. 1 Badong earthquake and subsequent 34 aftershocks at ML2. 0 or more were calculated using the P-wave first motion method; the main earthquake was normal fault dip slip type, and the slip types of the seismogenic rupture surfaces of the subsequent aftershocks to include normal dip slip (14 times), reverse dip slip (9 times), normal strike slip (9 times) and reverse strike slip (2 times). The M5. 1 Badong earthquake activities may be related to the stress adjustment caused by the rise of the groundwater level and the decrease of the frictional resistance between structural planes of rock formations due to the effect of reservoir water penetration, and related to the joint activities of the NE-strike Gaoqiao fault and the near EW -strike Daping fault.