In order to study the flow resistance and hydrodynamics of the pipeline separation mechanism under steady state flow conditions,the numerical simulation of the internal flow field of the separation mechanism was carried out using Fluent software,and the simulation results were verified by experiments.The pipeline separation mechanism model and the physical model of the watershed considering the compression spring were established.Through the distribution of the pressure,velocity vector and turbulent kinetic energy of the separation mechanism,the reasonable flow direction of the medium between the plug and the socket was analyzed.On this basis,the characteristic flow resistance of the plug at different inlet speeds was researched.The analysis results show that the flow of fluid medium from the socket to the plug is reasonable;the flow resistance of the plug increases with the increase of the fluid inlet velocity,and the increase rate is gradually increasing.Finally,the flow resistance characteristics of the plug were tested,and the error between the test value and the numerical simulation value was less than 5%.It shows that the numerical simulation result is correct to reflect the internal flow characteristics of the pipeline separation mechanism,which provides reference for determining the inlet velocity of the fluid and the optimization scheme of the mechanism.