Sequence image mosaic is an important and effective method to build a large "panoramic" scene which includes two main steps: image registration and intensity blending. In this paper, SIFT feature points are used to match images. SIFT are invariant to rotation, translation and scale changes, but the significant drawback is the high dimensional feature descriptor which lead to the expensive computation. So reduced SIFT descriptors are proposed to increase the speed of image registration. Linear combination methods of the matching points' gray-values are used for intensity blending. The experiments show that our method is useful and has high registration accuracy.