There are many parameters in analysis of are different in different period of seismic process, seismicity. The variations of those parameters and the earthquake forecast results of the parameters are not well. For existing some correlations among those parameters, 8 parameter, such as N（ML≥3.0）, b-value, η-value, A（b）-value, M〈value,Ac-value, C-value and D-value are selected for factor analysis method, and an synthetic parameter Wf., that reflects the temporal, spatial and intensity characteristics of seismicity, is made. The result shows that Wf, had obvious anomalous change before Jiujiang MsS. 7 earthquake in 2005, Jiangxi Province, and 14 Ms≥5.7 earthquake events in North China, can reflect the anomalous variation in temporal, spatial and intensity characteristics of seismicity well. Some problems in the factor analysis method are discussed also.