Fault isolation is an important technology to help guarantee that a DC system can be operated stably. A new fault isolation strategy is proposed to improve the traditional strategy which relies too much on a high-performance DC circuit breaker (DCCB). The new strategy makes use of the coordination between a flexible current limiting device (FCLD) and a DCCB. First, the cooperative mechanism between the FCLD and DCCB under permanent fault and transient fault is researched. Second, the arc transient characteristic of the interruption of the DCCB considering suppressed current from the FCLD is analyzed. Finally, a simulation is carried out on the Matlab/Simulink platform to verify the feasibility of the new cooperative strategy. The results show that FCLD can inhibit the breaking arc effectively; with this new fault isolation strategy, the DC system can finish ride through smoothly in the transient fault, while the DCCB can complete the no arc break in the permanent fault. The new strategy has reduced the breaking requirements for DCCB in terms of the DC system’s fault isolation, and improved the fault ride-through capability of the DC system.