The registration of multi-sensor images is a basic and key technique in image fusion process. This paper presents two different methods aimed to targets with different characteristics. For the small target, the registration is completed by two steps. First, using imaging principle, with focus, resolution and pixel dimension of CCD, the Field of View (FOV) corresponding relation between different CCD is established, and then it is used to complete FOV registration by cutting and zooming out the FOV of target. Second, the method of using Maximum Close Distance (MCD) matching to register target position is proposed. For the extend target, the 6-parameters affine transformation model to describe the target in 3-D space is established, and the imperfection of popular used 4-parameters model is analyzed. Then using the model and a set of matched points, the optimal parameters are fit through least square method. At last, the condition of use 6-parameters model to border the 8-parameters perspective model is analyzed. The experimental results show these two methods are all efficiency, and can eliminate the difference of the different sensor images.