Abstract: This paper analyzed the earthquake with M8 occurred in Quanzhou overseas in 1604, and also studied the seismic activity in Fujian combining with the modern seismic observation data. After analysis, it is known that the earthquake with M8 in Quanzhou overseas is induced by the stress accumulation in continental southeaster coastal area caused by westward compression of the Philippine plate. The important information is that there is a nearly NE-striking active fault going through the seismic source area, and most of the earthquake energy is released from this fault. The result of the analysis of this paper is that fault of Niushan-Brother island which is almost parallel to the main fault and 50 km far from it in east in the sea is the main seismic activity region in Fujian area since several hundred years, and it is the structure region which earthquake is easy to occur at present and in the near future in Fujian area, and it is also the main active fault which controls the seismic belt of South-east China coastal area.

Key words: Seismic activity, Fault of Niushan-Brother Island, Quanzhou M8 earthquake, Fujian area