The main structure foundation pit of Huli courtstation of Xiamen Metro Line 3 is located in offshore and water rich stratum. In order to improve the dewatering effect of foundation pit, through the calculation and analysis of foundation pit water consumption and dewatering wells, the layout method of large-diameter dewatering well points is selected, and the corresponding construction technology and operation details are put forward according to the quality problems prone to the construction of large-diameter dewatering wells, Finally, the monitoring data show that the dewatering effect of the foundation pit is good. Practice has proved that large-diameter well point dewatering, as a dewatering technology for foundation pit excavation of subway station, has a good application prospect.