When an HVDC transmission system is fed into a weak AC system, the fault recovery performance of the AC/DC system is poor after receiving AC system faults caused by induce commutation failures of the inverters, and there may be a problem that the AC/DC system cannot resume a stable operation state. This paper investigates the DC control functions that affect the dynamic performance of HVDC transmission systems. Based on the detailed electromagnetic transient simulation model of an actual HVDC project that feeds into a weak AC system, the original DC control parameters suitable for strong receiving AC systems are optimized through the simulation method. Taking the improvement of the maximum transmission power limit of the HVDC system as the evaluation index of the improvement effect, the fault recovery performance of the AC/DC system before and after the control parameters op-timization is compared and analyzed. The simulation results show that the optimization of DC control parameters can significantly improve the fault recovery performance, and it is the method that should be the priority to improve the transmission capacity of DC transmission projects fed into weak AC systems.