对化学气相沉积（ＣＶＤ）法制备ＳｉＣ的热力学进行了系统研究，考察了Ｈ２－ＭＴＳ，Ａｒ－ＳｉＯ－Ｃ，Ｈ２－ＳｉＯ－ＣｘＨｙ，Ｈ２－ＳｉＨ４－ＣｘＨｙ等体系，着重研究了温度、压力、载气量和初始反应气体浓度对沉积单相ＳｉＣ的影响，以ＣＶＤ相图的形式给出了计算结果，这些相图对ＣＶＤ法制备ＳｉＣ的实验具有指导作用． The thermodynamics of SiC prepared by chemical vapor deposition (CVD) have been systematically studied. The systems of H2-MTS, Ar-SiO-C, H2-SiO-CxHy and H2-SiH4-CxHy have been investigated systematically. The effects of temperature, The effect of carrier gas and initial reaction gas concentration on the deposition of single-phase SiC is given in the form of a CVD phase diagram. These phase diagrams are instrumental in the experiment of CVD for the preparation of SiC.