The pilot stage and the power stage are integrated in one spool by the 2D valve,which is easy to realize the fast work and high frequency response of the valve.It has the advantages of simple structure,stable performance and large power to weight ratio.The cavitation flow in the pilot stage of the 2D valve was analyzed by computational fluid dynamics.Taking the 2D valve pilot structure as the research object,Fluent software was used to compare the flow rate change,pressure distribution,gas volume fraction and other flow characteristics under different valve sleeve structures.The results show that the cavitation phenomenon is weakened after opening U-shaped grooves on both sides of the valve sleeve chute,which shows that the jet velocity on the analysis surface decreases and the gas volume fraction on the bottom surface of the chute decreases,indicating that the U-shaped grooves change the velocity streamline in the valve sleeve chute and weaken the shear flow effect of high-speed jet fluid.By further analyzing the noise spectrum of monitoring points in the valve sleeve chute,it is found that the noise of the two sides of the valve sleeve chute is reduced by 10 dB in the back of the chute where the cavitation is most serious compared with the original structure;at the exit of the model,the noise is reduced by 3 dB;in the middle of the chute,the noise sound pressure level increases slightly.It shows that the U-shaped groove with a width to depth ratio of 2.2 on both sides of the valve sleeve chute can indeed reduce the noise caused by cavitation in the 2D valve pilot stage.