The VOF two-phase flow model of FLUENT fluid simulation software is used to numerical analysis of nozzle jet flow field at different inlet pressures and different strike distances for needle nozzles. The speed of the flow field of the jet of the needle nozzle, the cloud diagram and the curve of the pressure distribution subjected to the cleaned parts were obtained. Then the influence of changes in the jet parameters of needle nozzles on the velocity and pressure of the jet flow field was studied. According to the result, as the inlet water pressure increases, the maximum velocity of the jet and the pressure on the part to be cleaned increase, but the increasing trend gradually decreases. As the striking distance increases, the cleaning range slightly increases, and the pressure value on the cleaned part decreases, but the degree of decrease gradually decreases. Then, when the inlet pressure is 30 MPa, the needle nozzle with a striking distance of 90 mm to 100 mm has the best cleaning effect.