Abstract: Compressed air energy storage(CAES) has a wide prospect in microgrids due to its advantages of long life and good economy. Direct-drive compressed air energy storage(DD-CAES) is widely used in distributed CAES systems due to its high flexibility, variable speed, high efficiency, etc. However, DD-CAES turbine power generation system is a nonlinear, strongly coupled and complex system, which is prone to power fluctuation during power tracking and frequency regulation using traditional proportional-integral(PI) control, which leads to frequency perturbation. Therefore, a dynamic simulation model of DD-CAES turbine power generation system is established, and a frequency regulation control strategy in DD-CAES based on improved linear active disturbance rejection control(LADRC) is proposed. The control system mainly consists of a variable operating point tracking system for reserving capacity and a converter control system for frequency regulation, and the analysis of the system dynamic response characteristics and frequency regulation characteristics shows that the proposed strategy can reduce the maximum frequency deviation(6.43%) and maximum frequency rate of change(11.65%) of the system under different working condition scenarios, which provides a theoretical reference for the establishment of grid-friendly direct-driven compressed air energy storage power plants.