The utility model relates to a water-drainage pressure-reducing well capable of disassembling and changing. The utility model mainly solves the defect that the traditional pressure-reducing well is easy to generate block. The utility model comprises an outer filtering well pipe and backfill sands at the circumference. A filtering body capable of disassembling and changing is arranged in the outer filtering well pipe. The filtering body can replace the backfill sands and a filtering cloth which are tightly adjacent to the circumference of the well pipe and perform the filtration effect in the traditional pressure-reducing well. The utility model has the filtration effect, and is the supporting body of block objects. The utility model can be reused by drawing the filtering body and cleaning or replacing the filtering cloth and a permeable foam in the filtering body. The utility model can be extensively used for the embankment foundation treatment of the embankment construction project on potamic bank.