The invention relates to a one-way flowing determination method for air-water relative permeability under the state of different hydrate saturations. The method comprises the following steps that a porous medium model is prepared, the porosity and permeability of the porous medium model are measured, a certain volume of hydrate formation inducer water solution and CH4 are injected into the porous medium model to generate the porous medium model under different CH4 hydrate saturations, N2 and water are injected into the porous medium model at constant speed according to the certain flow, the flow of the N2, the flow of the water, the pressure of the injection end and the pressure of the outlet end are measured respectively, and the air-water relative permeability is calculated according to the measured flow and pressure data. According to the one-way flowing determination method, on the basis of artificially synthetizing CH4 hydrates, the air-water relative permeability under the state of different hydrate saturations is measured with the combination of a porous medium model displacement experiment. The method is high in practicability and provides help for better understanding air-water flow rules in a natural gas hydrate reservoir.