Based on analysis of gravity and magnetic data of Zhaoqing area, it is considered that there are three groups of fault systems in the directions of near EW, NW and NE respectively in deep underground of this area. Among them, the one in the near EW direction is Zhaoqing -Guangzhou fault which is the main fault system and crosses over the whole area, and has a dissected depth of over 30 km; the trace of Zhaoqing-Kaiping fault is dear, but its dissected depth is shallower (about 10 km) ; Wuchuan-Sihui fault (in the NE direction) has a large scale, the dissected depth is about 20 km. The three groups of fault systems are also shown by the geological evidence. Combined with studies on the fault activities, it is indicated that the EW faults are the main active faults, and the intersection zones of the EW and NW faults are the main statutories of strong earthquakes.