In this paper, the cavitation phenomenon in hydraulic oil is investigated, and a new gaseous cavitation model based on the dynamic stimulation is examined. Before modeling, to confirm the characteristics of cavitation occurrence in hydraulic oil flow, the comparison of our previous experiment with the pressure distribution by CFD has been conducted. It is clarified that the region where the cavitation bubbles appear do not agree with the low pressure region, which indicates they are not in the case of vaporous cavitation. This comparison indicates that the gaseous cavitation has been occurred predominantly in the previous experiment. In modeling, the dynamic stimulation of unsteady flow field is assumed to play a major role in the liberation of dissolved air. The dynamic stimulation is transferred into the dimension of pressure and applied to the threshold pressure of liberation. Several models considering dynamic stimulation are proposed and comparison of the effect of those models has conducted to estimate the most appropriate modeling.