Abstract:There were 8 seismic parameters i.e. earthquake frequencyN(ML≥2.0),b-value,η-value,A(b)-value,Mf-value,Ac-value,C-value and D-value be used to reflect seismic activity characteristics in time, space and magnitude. Applying the factor analysis method variations of all these parameters since 1980 were studied before the Jiujiang M5.7 earthquake occurred on Nov.26,2005 in Jiangxi province and the synthetic parameter W favalue,major effective factors and certain correlation among these parameters were picked out.It showed that the camulative contribution rate of the four former factors reached to 95.14% totally. Being the four major effect factors,their contribution rate were 50.53%,23.50%,16.79% and 4.33% respectively.