As the metro lines become longer and traffic density increases, malfunction or refusing action of metro DC feeder protection device occurs from time to time, so it is of great value to design a more reliable protection algorithm. This paper analyzes the main DC feeder protection of DC railway traction power supply system. Based on the rising rate of current and current increment protection, a novel algorithm with judgment of voltage and current variation for DC railway feeder line protection is proposed. With the help of AFB process design method, a protection process for convenient setting and modification is realized. By analyzing the simulation results, the algorithm can remove non-metallic grounding fault and remote fault fast and accurately, while avoiding the impact of the locomotive starting current, so it’s very practical.