Abstract: Based on the analysis of the historical earthquake documents in North China and the 12 different features selected for describing the seismic activity pattern in different perio-ds, taking occurrence period of earthquakes M≥7 or 6< M< 7 from 1525 to 1900, prem-onitory phenomena before 7 and 6 magnitude earthquake have been analysised with pattern recognition method at twice.The precursor information before M≥7 and 7 >M≥6 eart-hquake have been obtained.According these, the seismicity from 1951 to 1984 period have been recognized by same method.The results are consistent with practice.