In order to research the effect of rotation on the flow and heat transfer characteristics of heat convection system in a closed cavity, a series of numerical simulations were carried out on the air flow and heat transfer characteristics in a closed cavity. The distribution characteristics of velocity field and temperature field by different Rayleigh numbers and rotating Rayleigh numbers by horizontal and vertical temperature gradients were obtained, as well as the local and average Nusselt numbers on high temperature walls. The effect of rotation on the thermal convection system by two kinds of thermal boundary conditions was discussed. The results show that for the heat convection by horizontal temperature gradient, the gradual enhancement of rotation makes the flow characteristics change from single-cell to multi-cell, and enhances the heat transfer performance of heat convection. For heat convection by vertical temperature gradient, the enhancement of rotation makes the flow tend to the steady-state flow characteristics, that is, the flow stability is enhanced, and at a large Rayleigh number, the enhancement of rotational action will first inhibit and then strengthen the heat transfer performance. Given the same conditions, the convective heat transfer performance by horizontal temperature gradient is better than that by vertical temperature gradient, and the stronger the rotation effect is, the more obvious the feature is.