The invention provides a prefabricated dewatering well which comprises a drill hole and a prefabricated part assembly, wherein the prefabricated part assembly is arranged in the drill hole; the prefabricated part assembly comprises a well pipe, a filter, a sediment pipe, a plurality of water stop sheets, a plurality of reserved grouting pipes and a plurality of sand filling pipes, wherein the filter is connected with the well pipe and positioned at the bottom of the well pipe, and the sediment pipe is connected to the bottom of the filter; the water stop sheets are fixed on the outer wall of the well pipe at intervals and positioned above the filter; the reserved grouting pipes and the sand filling pipes are arranged on the outer side of the well pip in the axial direction of the well pipecorrespondingly and are fixedly connected with the water stop sheets; the bottom ends of the reserved grouting pipes extend between the water stop sheet positioned at the top of the water stop sheetsand the water stop sheet positioned at the bottom of the water stop sheet; and the bottom ends of the sand filling pipes extend below the water stop sheets. The prefabricated dewatering well is largein water volume, good in water stop, good in subsequent maintenance effect, difficult in sand production and environmental protection, and can bring good influence to subsequent projects.