Based on the statistic data of loess seismic subsidence from the seismic micro-zoning works in Lanzhou and Baoji, many influence factors on the subsidence such as water content, void ratio, dry density and initial elastic modulus are analysed, and some more available, more concrete initial judging criterions for the loess seismic subsidence are obtained. Meanwhile the application of initial elastic modulus to the judging work is discussed.