The invention relates to a wafer defect detection system and method. The system comprises a processing unit, a control assembly, a displacement assembly, a detection assembly, and a signal acquisitionunit, the displacement assembly and the detection assembly are cooperatively arranged, and the displacement assembly controls the detection signal acquisition and movement of the detection assembly through displacement. The control assembly controls movement of the displacement assembly through an instruction and indirectly controls detection signal acquisition of the detection assembly, a signalacquired by the detection assembly and instruction information of the control assembly are transmitted to the signal acquisition unit, and the signal acquisition unit transmits the acquired signal tothe processing unit for processing to obtain defect information; the sensitivity requirement of an area array detector is reduced, and the detector cost can be effectively reduced; compared with a traditional scanning mode, the detection speed of the whole system can be greatly increased; and as the area array detector does not move in the area area exposure process, the problem of dithering andblurring of a traditional scanning mode can be solved, and the defect detection and recognition rate is increased.