Based on the analysis of the current ship hull spray technology,the principle and structure of the jet system of the ship spray robot were designed.Fan shaped nozzle was the key component of the new robot spraying scheme,and the study on its internal flow field characteristics is very important.Taking the four kinds of fan-shaped nozzles commonly used in shipyards as examples,the mathematical model was established by using CFD means according to the fluid theory,and the physical model was simplified according to the actual application field.The numerical simulation of the flow field in the nozzle cavity of the four kinds of fan-shaped nozzles was carried out respectively,and the comparative analyses of the pressure change curve and velocity change curve on the axis line of the four fan-shaped nozzles were carried out,the respective characteristics of the four fan-shaped nozzles were obtained,which provides a reference for the follow-up simulation of the fan-shaped nozzle of ship spraying robot.