Abstract: Hydrocarbonin gas hydrate mainlyincludes biogenic and thermogenic gases.However,within-creasing understandings of gas hydrate,newevidences are coming to light that there exists inorganic gashydrate related with volcano-hydrothermalism,whichis discoveredin ocean floor,subduction zone or ex-tensional valley.Fieldinvestigations and laboratory si mulation have manifested that,seabed serpentiniza-tion could generate inorganic gases.In fact,we have found gas hydrate related with volcano-hydrother-malism whose sedi ments have thin thickness and low organic carbon quantity.Therefore,inorganic gashydrae deposits should be paid attention toin the future.