In order to explore the effect of pressure loss on the performance of the isolating sleeve caused by the flow of the cooling working liquidity of the magnetic drive pump through the work gap of the isolating sleeve under different wall thickness,the flow field characteristics of the cooling circulating channel under the change of structure size and work gap of the isolation sleeve were discussed.Using SolidWorks and ANSYS Workbench,a three dimensional model of the cooling circulation channel was established.Based on SIMPLC algorithm and RNG κ-ε model,the characteristics of the internal flow field in the cooling channel of the magnetic drive pump were analyzed using Fluent simulation.The calculation results are as follows:the local pressure loss is caused by vortex formation of cooling working liquidity after entering the diversion hole;the maximum pressure loss is caused by the flow through the bottom of the isolation sleeve into the central return hole of the pump shaft;a pressure loss exists in the working gap of the isolation sleeve and decreases with the increase of the working gap of the isolation sleeve；when the wall thickness of the isolation sleeve is 0.8 mm and the working gap is 2.6 mm,the minimum pressure loss value is 2 000 Pa,which provides reference for the structural optimization of the isolation sleeve.