Two-layer spliced tensegrity structure can be used to design a flight simulator. Structural motions are caused by the shape changes. So, it is necessary to investigate the structural deformation. Considering the tensegrity structure with redundant cables is more resistant to destruction, this paper is devoted to analyzing shape changes of the two-stage tensegrity tower with redundant cables. Based on the principle of the minimum number of cables with different lengths, structural parameters of a two-stage tensegrity tower composed of two prisms with opposite rotation and other parameters are determined. Further, this paper defines five shape-changes: stretching, shrinking, flexure, shear and torsion. According to the five shape-change types, the axial, coupling, and complex deformations of a tensegrity tower are analyzed. Based on the energy-efficient cable-actuation strategy, this paper also studies the drive mode with the least energy dissipation for shape changes. The results show that the deformation energy consumption ratios of shrinking and stretching deformations are 9.634 and 12.674, respectively, under the optimal driving mode. The significance of the shape-change analysis is that it can predict the driving mode of the cable.