Abstract: Aiming to precise positioning field, A coaxial macro-micro composite actuator with voice coil motor as macromotion part and giant magnetostrictive actuator as micromotion part is designed. In order to realize the control of the macromotion part, a dynamic model of the macromotion part is established based on the principle of electromagnetic drive, the active disturbance rejection control system is designed for the macromotion part, which includes 4-order extended state observer and non-linear state error feedback controller. The 5-order S-type displacement curve path planning is used. The experimental results show that the maximum following error of the ADRC algorithm is about 0.155 mm, and the final location error is about 9 μm; Under load condition, the maximum following error of the ADRC algorithm is about 0.277 mm, and the final positioning error is 11 μm. The research results show that compared with PID algorithm, ADRC has lower following error and overshoot, and the final location error is within the micro positioning range of micromotion part, which meets the overall design requirements.