To address the DC overvoltage issue caused by AC-side faults in islanded offshore wind farms integrated via VSC-HVDC systems, this paper proposes a coordinated fault ride-through method combining VSC-HVDC voltage reduction control and offshore wind farm current reduction control. During the fault, the submodules of the VSC-HVDC system are first decoupled from the DC voltage to fully utilize its inherent fault ride-through capability. Then, based on system energy characteristics, a surplus power allocation-based energy equal-area method is proposed to directly characterize the safe operating region of VSC-HVDC sending-end power during faults. Meanwhile, a transient quasi-steady equivalent model of the wind farm with low-voltage ride-through strategies connected to the VSC-HVDC system is established. The relationship between AC voltage and the active power output of the wind farm during the quasi-steady process is derived, enabling precise derating control for the offshore wind farm. Finally, the proposed control strategy is validated on a PSCAD/EMTDC-based simulation platform based on the HVDC-connected Rudong offshore wind farm project. The simulation results demonstrate that the proposed control strategy effectively mitigates DC overvoltage without relying on additional braking resistors, thereby reducing energy losses improving economic performance.