When jet vane is exposed to exhaust gas and deflected at a typical angle, side force is produced and the missile is controlled. The vane is subjected to severe thermal and mechanical loadings by combustion gas. In this study, the high temperature tension tests of refractory metals, 3-D nonlinear numerical simulations and motor firing tests were performed to evaluate structural safety factor of the jet vane. The structural safety factor of jet vane was evaluated by comparing the numerical results with cold and hot structural tests of jet vane system. It has been found that a shaft supports most of thermal and mechanical loadings on the system and is structurally safe below 1400°C. From the comparison of firing tests and numerical results, the evaluation criterion of structural safety using the load and shaft deformation is more useful than using the equivalent stress.