In this paper, by means of the critical perturbation method, the formation of the stable solutions of spatial dissipative structure of Benard thermal convection, by incorporating the nonlinear forcing terms into the system after destruction of its equilibrium state, is examined. The results show that when the parameters are suitable values, the vertical and horizontal velocities, temperature change with the height, and the distribution of streamline on X–Z cross-section are basically consistent with the experimental results. The solutions have the characteristic of the supercritical bifurcations