The pumps used in the field of environmental protection dredging are mainly divided into wn dredge pump, wnq submersible dredge pump, QDP submersible sand discharge pump, etc. This series of pump impeller has wide flow passage, strong flow capacity, good cavitation performance and strong suction capacity, which can meet greater excavation depth and higher suction concentration. KSG / ksgh gravel pump or QDP submersible sand pump can be selected for dredging pumps with diameter of 400 and below. The gravel pump is a bracket structure, which is suitable for working in the cabin. The submersible sand pump is equipped with submersible motor, which can work underwater. The dredging pump with diameter of 450 and above can be selected as wn dredging pump, the cabin pump as wn type, and the underwater pump as wnq type. The speed of large-scale dredge pump is low, and the gear box can be used to adjust the speed. The dredge pump can adopt the bracket structure or the combination of bracket and gear box.