Observation satellites carrying high precision optical payload require extremely stringent pointing stability that may be violated in the presence of the disturbance coming from reaction wheels, cryocoolers or other actuating components onboard the satellite. The most common method to this paper development of a single axis active vibration isolator using electromagnet and its performance in isolating micro-vibration is presented. The main components of the developed isolator are membrane structure providing the isolator with the required stiffness and an electromagnet for active control. The performance test results show that additional damping can be achieved by active control without degrading isolation performance in high frequency region and that the developed isolator can effectively isolate micro-vibration.