The analysis of seismic magnitude is one of the most basic parameters, the magnitude deviation of the size of the direct impact of the usage of data and data reporting quality. This article according to the Jiayuguan seismic station digital record of nearly 3 years of data, which occurred during the 206 cases of moderately strong earthquake statistics, and" China seismic network report" provided standard magnitude comparison, the deviation of several factors analysis, the preliminary draw correction, is beneficial to improving the Jiayuguan station seismic analysis and its quality.