To calculate the deviation, average deviation, and standard deviation between single-station and average magnitudes in the Ningxia area, we performed a residual and multiple regression analysis of the magnitude, and selected 7 345 items of data from 1 782 seismic events recorded by the Ningxia broadband digital seismic network from January 2009 to December 2016. We analyzed the frequency distribution of the magnitude deviations and modified the calibration function of the local earthquake magnitude (M_L) to obtain the calibration function of the local uniform magnitude system for the Ningxia region. We obtained the attenuation characteristics of the maximum ground displacement and corresponding calibration function by multiple regression analysis. Our results show that the modified mean square variance of the magnitude reduces from 0.2370 to 0.2289, and the maximum modified magnitude value is 0.51.