Abstract: This paper proposes a strict geometric model of the calculation for the position and orientation parameters of the remote-sensing image with higher resolution.The method adopts threesteps of transformations based on parallel ray projection.The first step is reducing the three dimensional space to the image space by the similar transformation.Then,the small space is projected to the level plane,which passes the center of the image plane.Finally,the level image is transformed to the original declining image.Every step of the model is strict,and the map function of each transformation is the first order polynomials.The final calculation of the parameters is for the linear equations with good status.As a result,the problem of the relativity of image parameter calculation is solved completely.Some experiments are carried on for a lot of images with 10 m,3 m and 1 m resolution.All of the results are quite perfect.Thus,the validity of the strict geometric model has been verified.