This paper reports the study on coking rate and carbon formation route as a function of reaction temperature using the Ni catalysts in the CO2 reforming of methane. In this paper, carbon deposition on catalysts and its kinetics during reforming reaction were studied by using a thermogravimetric analyzer. Kinetic studies show that reaction orders of carbon formation obtained 1.33 (CH4) and -0.52 (CO2) by experiments on partial pressure of reactant gas, respectively. On the basis of model equation, the kinetic parameters for the coking reaction at different temperatures indicated that methane decomposition dominated carbon formation at lower temperatures (<600 ℃), while CH4 decomposition and Boudouard reactions become significant for coking in the temperature range of 600~700 ℃.