Ship docking plays an important role in the shipbuilding industry as a key part of maintaining and repairing ship structures. However, at present, the surface grinding process during ship docking relies on traditional manual work, which has problems such as low efficiency, long working hours and high danger. For this reason, a new cable-driven grinding mechanism was proposed, which used four cable to drive the grinding device to achieve three degrees of freedom of movement. Firstly, the dynamics model of the system was established by Lagrangian method. Then a Fuzzy-PID (proportional integral derivative) control strategy with cable tension optimization term was proposed on the basis of the dynamics model, which could achieve accurate trajectory tracking and ensured the cable was in tension. Finally, the effectiveness of the proposed control strategy was verified by numerical simulation. The results show that the control accuracy of the proposed control strategy is improved by 25% compared with the PID control commonly used in cable-driven parallel robots, which has high control accuracy and stability. The cable-driven grinding mechanism and its control strategy proposed in this paper can provide some theoretical support for applications such as surface treatment and precision manufacturing of large structural parts.