Through establishing the Green function database, the calculation work in the moment tensors inversion method is reduced, and speed for getting focal mechanism solutions of moderate-small earthquakes is improved. Using this method the focal mechanism solutions for 98 events with MI≥2.0 in 2008, in Qinghai province are calculated. The result is discussed also. The research work is helpful to using regional digital seismograph network data for giving focal mecha nism solution of small earthquakes.