Abstract: The destructive Qiongzhou earthquake (July, 13, 1605) which occurred in the northern part of Hainan Island is historically an event having the most severe damage in South China, and causing the land-collapse on a large scale to form a part of the sea. The present investigation gives its intensity as XI, M = 7³/₄-8, h=22km?, epicenter location as N19?59', E110?28'. The magistoseismic area is shaped like a partly inverted tablespoon with its main long axis trending NEE, but being intersected east of Mt. Qiongshan by another long axis running NNW. The principal seismogenerating fault is in NEE direction and a NNW-trending fault is across it.This earthquake took place in a tectonic junction between two sets of horsts and grabens, namely, between the NEE trending strongly uplifted Fushan-Meiting horst and the intensely depressed Str. Qiongzhou graben in N. Qiongzhou district, and in NE Qiongzhou between the NNW running -strongly uplifted Yunlong horst and the intensely depressed Dongzhai Harbour graben. It happened in a horizontal stress field with predominantly NW strike (300氨) but resulted from the strongly differential vertical move-ment in the earth's crust In short, this earthquake was induced probably by a pair of X-shaped NEE (predominantly) and NNW-running shearing faults and was the consequence of their growth, development and displacement.