Abstract: Sanzao fault zone is a branch of the western beam of Lianhuashan tectonic zone, and also the extension of the fault zone on the west bank of Pearl River estuary. This fault was defined as an active fault by existing data and research. The distribution characteristics and activity of Sanzao fault zone in Hengqin area were studied through detailed field geological survey, micro-motion method, shallow seismic exploration, drilling verification and clastic rock age test. The results show that the overall strike of Sanzao fault zone is NE-NEE trending and dipping north west, which dislocated the mottled clay of the Upper Pleistocene deltaic deposits. The results of optically stimulated luminescence (OSL) dating of clastic rocks in the fault zone are (27.77±2.99) ka and (22.24±1.04) ka, indicating a large-scale brittle fault activity in the Late Pleistocene in Hengqin area. The research could provide references for urban construction and disaster prevention and mitigation in Guangdong-Macao in-depth cooperation zone in Hengqin area.