Abstract: The key technology of accurate rectification for remote sensing images with high resolution (RSIHR) to acquire orthoimage is introduced. The first is to settle the strong relativity of the parameter calculation of RSIHR. After the rational polynomial coefficient (RPC) used by IKONOS and QuickBird images and RPC-based block adjustment are presented, the strict geometric model based on affine transformation is introduced. The second is the generation of DTM, needed in the accurate rectification of RSIHR. Because the approximate epipolar image pair of some RSIPHR remains quite large y -parallax, 2D relaxation matching based on feature points should be used.