Abstract: The kinetic features of the gasification with H2O-H2 mixture of carbon deposited on the nickel catalysts for steam reforming of naphtha are reported in the temperature range 723-973K. Investigations were mainly carried out in a TG-monitored flow reactor system. Two kinds of industri nickel catalysts, the domestic Z402 and the British ICI46-1, were selected for study. Empirical rate equations of carbon gasification with H2O-H2 mixture were obtained for the lower and the higher temperature ranges respectively. Empirical rate equations of carbon gasification with steam alone were also given for comparison. TG-scan of the carbon gasification process revealed that steam alone does have an oxidizing effect on nickel catalyst, and that, with H2O-H2 mixture of suitable H2O/H2 ratio, this effect can be eliminated. This will prevent the catalyst from the undesired deterioration due to the repeated oxidation and reduction.It was shown that H? in the H2O-H2 mixture has two opposite functions. It has inhibiting effect through its negative reaction order. But it can also have on accelerating effect by keeping the Ni catalyst from being oxidized by steam. This is of significance for the lower temperature region where the rate of carbon gasification is usually low.