In this paper, SiC with the morphologies of both particles and whiskers was grown on graphite surface by chemical vapor reaction method under different pressure conditions. According to these experimental discoveries, designed experiments with different reaction pressures and temperatures were studied in detail, and then, the influence factors were analyzed in theory. The results show that the shapes of the formed SiC are influenced mainly by the total pressure of the system. Higher total pressure is in favor of larger concentration of CO and then tends to form SiC whiskers. In addition, temperature significantly affects the size of SiC, higher temperature results in shorter length and further quantity of the SiC whiskers as well as larger diameter of the SiC particles. Based on these results, controllable synthesis of silicon carbide whiskers and particles can be realized in accordance with the requirements of application.