Abstract: To analyze the stuck-on phenomenon of the servo valve slide valve in wide temperature operating conditions, a three-dimensional model was established for temperature field simulation based on the Solidworks software. Synchronously, a coupling field of thermal and structural analysis was established on the Ansys workbench platform to simulate the temperature field distribution of the electro-hydraulic servo valve side valve and the thermal deformation of the valve sleeve and the valve core under high temperature conditions. Analysis results show that, when the oil temperature drops, the heat transfer is in the form of ring in the valve body, inducing the variation of the radial clearance between valve core and valve sleeve. Also the analysis results provide a variation law of the radial coordination gap between the valve core and the valve sleeve along with the temperature change.