Abstract: To study the internal flow characteristics of an axisymmetric vectoring nozzle with external flow at the geometric deflective angle varying from 0° to 14.2° with deflective angle rate of 40°/s,the numerical simulation has been conducted with collocated finite volume scheme and Pressure Implicit Split-Operator (PISO) method.The influence of different Nozzle Pressure Ratio (NPR) and the external flow on the performance of the axisymmetric vectoring nozzle,the relation between the gemeotric deflective angle and thrust vectoring angle have been analyzed.The thrust vectoring angle oscillates after the separation flow occurs on internal wall.The results will afford the reference for designing these nozzles and their control.