Abstract: An experimental setup has been built to study the stability conditions of gas hydrate. The stability conditions of methane hydrate in solutions with different salt concentration are preliminarily investigated using multi-step dissociation method. In this paper, P-T conditions of methane hydrate have been measured in four kinds of solutions containing various concentrations of NaBr and/or KBr. The results show that the influence of Na⁺ ion under certain P-T conditions is stronger than K⁺ ion under same concentration. In the NaBr and KBr solutions with concentrations of 0.2mol/L and 0.3mol/L, the equilibrium points of methane hydrate were (0.5±0.1) K and (0.2±0.1) K, and (1.0±0.1) K and (0.5±0.1) K respectively, lower than those in a pure water system.