In order to improve the residual stress and optimize the process conditions of reverse epitaxial 3C-SiC thin films，the 3C-SiC film based on the n-Si (111) was prepared with the methane and hydrogen mixture at the ratio of 1:10 using LPCVD technology. The 3C-SiC films were characterized by X ray diffraction, laser Raman spectroscopy and field emission scanning electron microscopy.  The experimental results show that the optimum reaction temperature is 1200℃, and the reaction temperature either too high or too low is not conducive to grow 3C-SiC film. When the reaction temperature is 1200 ℃, the film thickness and the concentration of defects will increase correspondingly with the increasing reaction time, so that the crystalline quality of the film can be decreased accordingly. However, when the reaction temperature is 1250 ℃, increasing the reaction time will not only increase the thickness of the film, but also reduce the residual stress in the film, and improve the crystalline quality of the film. In addition，the results show that the process of constant temperature and constant time annealing can further reduce the intrinsic residual stress, improve the crystalline quality of the thin film and crystal lattice mismatch.