Orbital perturbations caused by the space environment will induce deviations compared with the prescribed motion trajectory or dynamic performance of the tethered satellite system (TSS). To comprehensively investigate the effects of the orbital perturbations on the TSS, a precise variable-length element that can describe the large deformation and flexibility of the tether is adopted in this paper to predict the deployment dynamics considering orbital perturbations, including atmospheric drag, solar pressure, lunisolar gravitation, and J2 perturbation. To this end, the variable-length element using arbitrary Lagrangian-Eulerian (ALE) description in the frame work of absolute nodal coordinate formulation (ANCF) is developed firstly. Subsequently, the dynamic governing equations for the TSS are established in the context of ANCF with the employment of ANCF reference node (ANCF-RN). Effects of orbital perturbations including atmospheric drag, solar pressure, lunisolar gravity and J2 perturbation on the dynamics of an optimal deployment are analyzed numerically. It is shown that the orbital perturbations except the J2 perturbation will induce the out-of-plane motion of the TSS. Additionally, the tether tension is less affected by the orbital perturbations. By contrast, the lunisolar gravitation will induce a deviation on the motion path of satellite, which should be considered in the design phase of the TSS.