Computational studies are conducted on supersonic nozzles to investigate the possibility of utilizing counter-flow in thrust vector control. In this work, the design Mach number of the symmetric supersonic nozzle is set to be 2.5. For the validation of methodology, numerical results are compared with experimental data referred from the literature. Two-dimensional numerical simulations are based on well-assessed standard k-ε turbulence model with standard wall functions. Second order accuracy is ensured to reveal more details of countercurrent shear layers. The deflection angle and secondary mass flow ratio were studied for a wide range of nozzle pressure ratios (NPR) and secondary pressure ratios (SPR). The results indicate that deflection angle and secondary mass flow ratio are found to be decreased with increasing of NPR. The secondary mass flow ratio and deflection angle decrease with the increase of SPR. The secondary mass flow rate must remain under 2.4% of the primary flow to obtain efficient thrust vector control at high Mach number.