Abstract: Based on RANS equations, the gas leakage mechanism of ventilated supercavity has been simulated using a inhomogeneous model with the consideration of gas-water interactions under the condition of low Froude number. The influence of different turbulence models to gas leakage coefficients has been investigated. The gas leakage rule of supercavity has been achieved at different Froude numbers and ventilation coefficients, the results accord well with that of water-tunnel test phenomena. The numerical method has a good calculation precision by comparing the results with that of classical empirical formulae and has important significance to further investigate the physical mechanism of ventilated supercavity.