This report verified the existing gas-phase elementary reaction models for chemical vapor deposition (CVD) of silicon carbide (SiC) from methyltrichlorosilane (MTS) developed by Iowa State University (ISU model) and Scientific Research Associates (SRA model). SiC-CVD involves consecutive reactions starting from gas-phase reactions of MTS to form intermediate species, followed by their surface reactions. In this study, the models were verified with respect to the overall decomposition rate constant of MTS (kMTS), which was evaluated at 960–1000°C using a quadrupole mass spectrometer (QMS). The relationship between the MTS retention ratio and residence time showed that the overall loss rate of MTS followed first-order kinetics. The obtained kMTS was subsequently divided into the overall gas-phase reaction rate constant (kg) and the overall surface reaction rate constant (ks) considering the contribution of these two factors by studying reactors with different surface area to volume (S/V) ratios. Then, kg was compared with the overall MTS decomposition rate constant calculated from the ISU (kISU) and SRA models (kSRA). Neither model reproduced the experimental results exactly, but the inclusion of elementary reactions and gas-phase species may improve their accuracy. The improved model is under construction and will be reported in a future study.