Based on the potential theory, the relationship among the variation of rotor inflow, the induction factors and the thrust coefficient was derived, and the dynamic wake model for wind turbines was established. This model improves traditionally used equilibrium wake model which is a quasi-steady approach to transient aerodynamic analysis, and can reflect the real dynamic induced velocity field and dynamic lag of wake. Therefore, this model is more applicable to analyze the transient aerodynamics of wind turbines. Using the developed computer program, the aerodynamic performance of a 1.3 MW stall-regulated wind turbine was calculated. The comparison of the calculation results between the equilibrium wake model and dynamic wake model indicates that the dynamic wake model is more rational and applicable.