Influences on relative pixel displacement in overlapping area of mechanical assembly CCD focal planes in remote sensing cameras are studied. Various factors, such as stability of the platform, wavy terrain, distance between two spliced CCDs, are taken into account. The relative pixel displacement of normal photography due to the wavy terrain is studied by using the geometric relationship of central projection. Starting from the collinear equation, the exact mathematical model of the relative pixel displacement is derived by using analytic method. According to the model founded and an example with engineering application, the corresponding stabilized platform is determined, and the numerical results are given. The study has engineering sense and practical value in actual project.