Abstract: Natural gas hydrates, with special physical and chemical characteristics, have a broad industrial application prospect, the formation rates of which are relevant to temperature, pressure and gas to liquid mass transfer conditions. An experiment on effects of composite promoting agents composed of surfactants and liquid hydrocarbons on hydrate formation was conducted and hydrate formation temperatures, pressures, induction times and rates with different composite promoting agent portfolios were measured. Surfactants used were sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) and 2octyl sodium dodecyl sulfate (GC20S), and liquid hydrocarbon additives utilized were cyclopentane (CP) and methyl cyclohexane (MCH). It appears that all these combinations of composite promoting agents can promote hydrate formation. Type II hydrate formation conditions with composite promoting agents composed of GC20S and CP are the mildest and the induction times are the shortest; type H hydrates formation conditions with composite promoting agents composed of GC20S and MCH are the mildest and the induction times are the shortest.