Abstract: To improve the estimation result of the extended state observer (ESO) and to solve the problem of parameter tuning of in the active disturbance rejection control, we propose a linear active disturbance rejection control strategy based on the N₄SID numerical algorithms for subspace state space system identification (N₄SID). We use the N₄SID subspace identification method to determine the unknown parameters of the system model and the parameter of the linear active disturbance rejection control (LADRC) to reduce the uncertain factors of the controlled system and to improve the ability of the extended state observer to estimate the generalized disturbance of the system. Simulation results show that the proposed method effectively improves the control effect of LADRC and the estimation ability of the extended state observer.