The mud lift pump, as the core functional unit of riserless mud recovery drilling, drives the cutting-bearing mud stored in the suction module to flow back to the drilling platform along the upward return pipeline. This paper takes centrifugal pumps as the research object, constructs a computational model of the pump through CFD-EDM, conducts full-scale flow field simulation, and studies the impeller design, flow field and particle transport distribution, and hydraulic performance tests of the sample pump. The research results show that the pump has good working characteristic indicators, and its hydraulic performance meets the design requirements, the pump can be applied to deep-sea riserless drilling operations. And it also shows that the design method and experimental process of the pump are reasonable and feasible.