In order to improve the ability of cavitation water jet to clean the surface of the net, an Inner wall-Central body cavitation nozzle is designed. The numerical method of cavitation nozzle cavitation flow CFD was used to compare and analyze the simulation and theoretical solution, and the reliability of the two-dimensional axisymmetric cavitation flow numerical model based on the two-equation turbulence model was verified. The numerical calculation of the cavitation flow of the Inner wall-Central body cavitation nozzle in the environment of submerged water jet was carried out, and the influence of the Inner wall cavitator and the Central body on the cavitation effect of the nozzle was obtained, and the influence of water depth on the cavitation effect was calculated and discussed. The results show that： The water jet passes through the nozzle throat, creating cavitations on the surface of the Inner wall cavitator and the Central body, respectively； The Central body cavitation effect is better than that of the Inner wall cavitation, but the effect on jet blockage is stronger； The Inner wall cavitator increases the nozzle throat pressure and further improves the cavitation effect of the Central body； Both the Inner wall cavitator and the Center body can reduce the sensitivity of the nozzle cavitation effect to water depth. This study provides a basis for the research of cavitation flow dynamics mechanism for nozzle design of net cleaning in aquaculture cages, and provides design ideas with low cost and high efficiency.