The cavitation performance of the dredging pump is an important index to determine the construction capacity of the super large trailing suction dredger. However，the domestic dredging pumps often lack cavitation performance data. Taking the first domestic super-large 18，000 m3 trailing suction hopper dredger as the object，the cavitation performance of dredging pump is researched，and the fluid dynamics model is established. Firstly，the relationship between flow rate and flow head，flow efficiency，flow power are obtained，and the reliability of the model is verified by comparing with the experimental data. Complete cavitation model is applied to study the cavitation performance，and the critical efficiency decrease value which is more strict than the abroad criteria is used as the critical cavitation point. Then the NPSHr data of different flow rates at a certain dredging speed are obtained. The research methods and conclusions are used for reference for engineering and specific dredger.