An effective tracking method is proposed to solve the problem that the electro-optical tracking system in Missile Range easily loses the real target during the target separation. Before target separation, the error correcting value of the theoretical trajectory is obtained by the theoretical trajectory correcting algorithm. In the phase of target separation, the theoretical trajectory of the target is corrected by the error correcting value firstly, and then the fuzzy clustering association algorithm is applied to calculate the similarity between the measuring data of the target from sensors and the corrected theoretical trajectory. The similarity helps to identify whether the measured data is from the real target or not. Experimental results show that the authenticity of the target can be determined effectively. The identified results can be used as the decision-making basis of the servo sub-system and TV trackers, which can improve the continuous tracking probability of the electro-optical tracking system in the target separation.