Using P wave first motions and the maximum velocity amplitude ratio of Pg and Sg waves,the focal mechanism solutions of the Shanxi reservoir earthquakes above ML 2.0were calculated.The time and space characteristics of the focal mechanism solutions parameters were obtained as follow:most of the main press stresses are North-south oriented,most of the main tensile stresses are East-west oriented,the stresses are almost horizontal,most of the slips of the planes are above 60°,and most of the faults are strike-slip type.Both of the azimuths of the Paxis have the trend of first deviation and then recovery before some MS4.0earthquakes.In the range from 27.66°to 27.69°N,focal mechanism solutions parameters have a good consistency.Most of the azimuths of the P-axis are 0±30°and 180±30°,and most of strikes of the plane are 45±15°and 135±15°.Most of the slips with focal depths deeper than 4km are between 70°and 90°.