Abstract: For the dynamic frequency regulation of microgrid,the system inertia is quantified. The influence of the virtual inertia control（VIC）parameters and wind power permeability on dynamic frequency deviation is then explored from the prospect of inertia.For the steady-state frequency regulation of microgrid,a scheme of variable de-loading ratio is proposed,to achieve the balance of the power reserved from de-loading and the additional power needed by the droop control. In this way,the preset frequency regulation target can be reached. Based on the reserved power from de-loading,the optimal drooping control parameter is obtained by optimization algorithm,taking the droop control parameter of doubly-fed induction generator（DFIG）as the control variable. Through simulation,the VIC parameters are determined from the prospect of inertia and the effect of permeability on the dynamic frequency is analyzed. The optimized droop control parameter and the scheme of variable de-loading ratio can effectively improve the frequency stability of the microgrid.