To develop scaling laws for source models, two data sets of global parameters are compiled from the data of reference [3] with modified and supplied by the NGA data bases. These data include parameters of 189 and 204 earthquakes, among which 127 from reference [3], 31 modified from NGA, 31 and 46 newly collected respectively from the two versions of NGA data bases. Empirical and semi-empirical relations between moment magnitude and four source global parameters; the area, width, and length of the rupture plane; and the average slip on the plane are presented for three rupture types and five (three) magnitude intervals. The result coefficient values of the relations do not differ significantly from those in reference [3], and the largest relative differences are 12.4% and 8.4%. The deviations of data to the relations appear to decrease, i.e., the larger the data set, the more stable the statistical relation. To demonstrate the effect of the improvement in this paper, high-frequency ground motions at four near fault points are synthesized by means of source models established for a M7.0 strike slip shock with the scaling laws. The results show higher mean spectral amplitudes and peak values than those determined by reference [3]. The relative differences of the means are about 4.6%~23.0% and decrease with increasing distance.