The utility model relates to a dredging pump, in particular to the dredging pump for a large-sized cabin. The pump comprises a support body, wherein a bearing component is fixedly installed on the support to support the shaft of the pump; a pump housing is fixed at the front end of the support; a pump cover is installed at the front end of the pump housing with a cylinder block; and impellers are arranged in the cylinder block and are installed at the front end of the pump shaft. The pump is characterized in that the radial gap between the cylinder block and the pump housing is smaller than the wall thickness of the pump housing or the cylinder block. According to the utility model, the water cavity gap is optimized and reduced through the stress analysis; the size of the pump housing is reduced to reduce the weight; and the bearing area of the pump cover is reduced; with the equal pump cavity pressure, the stressed area of the pump cover is reduced so as to reduce the stress, which facilitates the sealing between the pump cover and the pump housing with a better effect.