Cable-driven parallel robots (CDPRs) can provide a high speed and a heavy payload in a large workspace. The main challenge of CDPRs stems from the dynamic control, in which all cables must coordinate with each other to remain in tension, and the cable-driven form may lead to model uncertainties. To solve it, the second-order sliding-mode (SOSM) is combined with the multi-cable synchronization idea to propose a new SOSM-based synchronization control (SOSM-SC) strategy for CDPRs. The goal of the cross-coupled control (CCC) approach is to improve the synchronization motion relationship between all cables and guarantee better trajectory tracking control, while the SOSM can restrain the model uncertainties and external disturbances. The Lyapunov theory is utilized to prove the asymptotic stability of the closed-loop control system of CDPRs. Trajectory tracking experiments indicate that compared with the existing synchronization control (SC) strategy and the augmented proportional-derivative (APD) strategy, the proposed SOSM-SC strategy significantly reduces the cable tracking error and the cable synchronization error and ultimately improves the control accuracy for the mobile platform. Tracking experiments of the anti-disturbance indicate that the SOSM-SC strategy can retain good tracking accuracy under external disturbances.