In this paper.the hardware designing priciple and the soltware designing characteristic of tracking system of real-time dual-mode image used for visable or inlrared light are introduced The features of the mass centroid tracking algorithm.the characteristic matching algorithm and the dillerential tracking algorithm have been discussed. On the basis of these .the dual-mode conlidence and fulion tracking algorithm are presented .and analysed. Finally.the controlled tactics of the servo system is briefed