Abstract: In this paper, according to the historical documents, the perceptible area, destructive area, meizoseismal area and the distribution of aftersho-okes of the strong earthquake (7.5) in Northern Shanxi Province on May 21, 512, as well as the seismic activity of Northern Shanxi Province bef-ore the earthquake are studied. The epicenter of the strong earthquake may ue located in 38°50'N and 112°50'E in Dai County. The direction of the causative fault is NNE.