According to the local magnitude definition by Richter，we collected local earthquake data recorded by the Guangdong Digital Seismic Network and measured the maximal amplitude on simulated Wood-Anderson seismograms of the broadband seismograms，which were simulated in frequency and time domain respectively. Using these two kinds of data，two calibration functions of the local magnitude scale for Guangdong region have been obtained. The correction of the 44 seismic stations of the Guangdong Digital Seismic Network has been calculated by analyzing the ML residuals for each station. Using a Z-test，we found that the correction of 38 stations was significantly different from 0.The application of the new local magnitude scale and station correction，the overall variance of the mean magnitude estimates have been reduced by 30%.