Abstract: The number of wind turbines connected to the grid is steadily increasing, which detrimentally affects the system frequency characteristics, and consequently limits the maximum penetration level of wind generation. In this paper,based on the key objective of rising proportion of wind generation, inertial response of wind turbines under frequency disturbance was analyzed. Also, demand and strategy of high-penetration wind turbines participating frequency control were proposed. Inertial response characteristics of wind turbines were analyzed from three aspects, including difference of physical structure of wind generators, relationship between electromagnetic torque and frequency, and use efficiency of kinetic energy of rotor. Taking the IEEE-39-bus system for example, it was found that frequency problem has been the constraint condition of penetration level of wind generation,which gives rise to demand of wind turbines participating frequency control. Strategy for enhancing proportion of wind generation was proposed. By virtual inertia control and droop control, wind turbines can provide short-term and long-term frequency support. The rate of change of frequency（ROCOF）,frequency nadir and quasi-steady state frequency are all considerably improved, which can increase penetration level of wind generation as well as guarantee power system security.