A spool type high temperature control valve is developed to control the flow rate of high temperature fuel supply for scramjet engines in this paper. The clearance between the friction pairs of the spool and sleeve is crucial for the proper performance of the valve working at the temperature as high as 700 K. The high temperature environment may cause problems to the valve, for instance the thermal deformation of the valve materials, the failure of the friction pairs inside the valve and even the damage of the operating proportional electromagnet. Therefore the thermodynamic analyses of the valve are carried out using 2D finite element analysis method. The heat transfer and fluid dynamic models, as well as the boundary conditions are introduced. The heat flux through the fluid/solid interface is calculated to connect the heat transfer models inside the solid domain and the fluid domain. By solving both the heat transfer and turbulent flow models in the solid and fluid domains, the flow field distribution inside the flow channel and the thermal field distribution inside all the parts of the valve are shown. Suggestions on the design of the valve are given according to the thermodynamic analysis results.