Abstract: In this paper, a generalized inversion method for the determination of hypocenters probability distribution based on P and S arrivals of near earthquakes in a medium with vertically heterogeneous property and its computer program are presented. As an example, by using this method, a numeridal result based on the data recorded by a temporary digital station network in Luan Xian region in North China is given, and it is compared with the result based on the same data by using the existed computer program HYP081.