In the proton exchange membrane fuel cell (PEMFC) for vehicles, the changes in gas composition and oxygen accumulation may exist during the parking process even by using a shut-down strategy of oxygen consumption, which can lead to the hydrogen/air interface. However, this process of oxygen accumulation is often ignored. Thus, in this work, the diffusion rate of the gas, the gas composition changes, and the starting voltage of the PEMFC stack are discussed. According to the experiment, it is proved that the poor gas tightness of the stack results in the formation of the oxygen inside the stack during the parking process and the threshold parking time of no hydrogen inside the stack is above 1 h. Then, a parking control strategy is proposed by injecting hydrogen into the anode, and the hydrogen injection cycle is set as 1 h by the anodic hydrogen concentration. Based on the strategy, the starting voltage of the fuel cell is declined from 18 V to 3 V. That means the hydrogen/air interface is declined. Therefore, the durability of the PEMFC for vehicles can be enhanced.