采用Evernden的线源模型推导出了用震中烈度I_o,极震区面积S和震源深度H计算震级的公式。将全国分成八个区,采用1900年以来在我国发生的163次M_s≥4.7地震,回归出全国和分区的公式。对结果分析表明,分区结果明显优于全国统一的结果,更优于只用震中烈度计算震级的结果。但震源深度项所起的作用似乎不大。对结果进行了比较和讨论。 Using Evernden’s line source model, the formula for calculating magnitude using epicenter intensity I_o, polar shock area S and focal depth H is deduced. Divided the whole country into eight districts and adopted 163 M_s≥4.7 earthquakes that occurred in our country since 1900, so as to return the national and district formulas. Analysis of the results shows that the result of partitioning is obviously better than that of national unity, which is better than the result of calculating the magnitude only by the intensity of epicenter. However, the depth of source term does not seem to play a role. The results were compared and discussed.