The seismic tendency in mainland of China after west to Kunlun Mountain Pass M_S 8.1 earthquake is analysed by the comparing of seismicity in different active period, the change of dynamical condition around mainland of China and the migratory rule of strong shock in western China. The effect of M ≥ 7.5 earthquakes in western China on seismicity in eastern China is statistically analysed too. The result shows that the fifth active period of seismicity since 1900 is going to end, but the seismic frequency and energy releasing are not enough, and the dynamical conditions on the border of China dosen't change after the M 8.1 earthquake, so it is possible to occur M ≥ 7.0 earthquake in mainland of China in future several years especially in northwestern area of western China. The effect of M 8.1 earthquake on seismicity in eastern China is about M 6.5