Abstract: The complex inner flow-field of the thrust vectoring nozzle based on secondary gas injection was numerically simulated using three-dimensional average Reynolds equations and the κ-ε turbulent models. The influences on the thrust vectoring efficiency and the thrust ratio of different injection parameters and the nozzle pressure ratio were analyzed and investigated. Results indicate that the effects of the position injection orifice, the injection angle and the injection mass flux on the vectoring angle couple each other.When the vectoring angle reaches its maximum value in design conditions, these injection parameters couldn-t reach their respective best value simultaneously.When the vectoring angle increases, The thrust ratio decreases and the thrust loss increases. The thrust vectoring of the rectangular injection orifice is better than that of the circular injection orifice. The vectoring angle increases with the decreasing of the nozzle pressure ratio.