This paper deals with the seismicity pattern before the earthquake ac-cording to seismological data of China.
The results obtained from this work show that there are three abnor-mal patterns,namely,gap of the seismicities,epicenter shift and fore-sock's belt densely-distributed and the concept of "gap belt of seismicity" has been proposed.Besides,according to the b-value and the energy-releasing curve,it is inferred that the occurrence of the M 8 earthquake was cau-sed by an active tectonic zone with a long time action