As the function, scale and complexity of the hydraulic system gradually increase, the failure rate of the hydraulic system also increases.In order to improve the reliability and safety of the hydraulic system, the internal flow field of the outlet pipe of the anchor machine hydraulic pump was studied in the case of the system hydraulic oil produced particle pollution. Pipeline flow schemes with different particle pollution levels were designed, and Fluent was used to simulate the flow field inside the model. The pollution level of hydraulic pipeline was evaluated based on boundary layer theory. It provides conditions for improving the level of ship hydraulic equipment state detection and the ship intelligence on the whole.