Flow fields of 2-D shock vectoring nozzle are calculated by the finite volume method based on 2D Reynolds average Navier-Stokes equations, RNG turbulent model and considering the variation of specific heat at different temperature. The results show that there has been some changes of the nozzle flow fields such as upper moving of the shock wave, the abatement of the shock wave amplitude and the increase of the velocity of the nozzle outlet compared with the calculation of constant specific heat. By further analyzing, the thrust coefficient, the thrust vectoring angle and the vectoring effectiveness all have increased in contrast between the variable specific heat calculated results and the constant specific heat numerical results.