Abstract: To investigate the applicability of different sub-grid scale models in simulating the unsteady cavitation flow around a two-dimensional Clark-Y hydrofoil, the homogeneous flow assumption and the Zwart cavitation model was applied in present work. Four sub-grid models Wall-Adaptive Local Eddy Visibility（WALE）, Smagorinsky-Lilly, Algebraic Wall-Modeled LES Model（WMLES） and Dynamic Kinetic Energy Sub-grid Scale Model（KET）) were selected to close the controlling equations. The unsteady flow characteristics, such as airfoil lift drag coefficient, time averaged velocity distribution of flow field at different positions and periodic change of cavitation morphology, under cloud cavitation predicted by different sub-grid scale models were obtained and compared with corresponding experimental data. The results show that: compared with the prediction results of other sub-grid scale models, the average lift coefficient simulated by the WALE model is in the best agreement with the experimental values, for which the relative error is only less than 1%, and the change of the predicted instantaneous lift coefficient is close to the corresponding experimental data. Besides, the WALE model can be more applicable to accurately capture the unsteady evolution characteristics of cloud cavitation period, including the growth of attached cavitation near the leading edge of the hydrofoil, and the break-off of sheet cavitation and the shedding dynamics of cloud cavitation under the effects of re-entrant jet. Based on the numerical results of the WALE model, the vortex structure near the trailing edge is expressed by the Q-criterion, and it is found that the unsteadiness of the cloud ca-vitation induces the generation of vortex in the wake.