A method of shrouded radar target surface temperature field calculation was proposed in this paper, in allusion to the important strategic position of radar target during military attack. Firstly, the structural characteristic of radar target was analyzed, based on which radar target was simplified into spheroid. Secondly, radar target three-dimensional temperature field model was established, including building heat balance equation in spherical coordinates, analyzing boundary conditions, establishing thermal equilibrium model. Finally, through simplifying the surface temperature field model and the boundary condition of the radar target, target surface temperature field was obtained by solving the temperature field model, and a method based on reduced dimension finite difference iterative was proposed. The experimental results show that the calculated distribution of temperature field and the generated infrared simulation images accorded with actual situation, and temperature variation was consistent with the actual, so the temperature field model established and solution method were feasible, which provided basic parameters and theoretical basis for further study on the target infrared radiation characteristics.