The present invention provides a hydrogen exhaust system for a fuel cell vehicle, which is configured to actively control an exhaust path of hydrogen discharged from an anode of a fuel cell stack to maximize the safety of the vehicle by minimizing the possibility of explosion due to hydrogen exhaust and ensure the silence of the vehicle by minimizing noise generated during hydrogen exhaust. Moreover, the present invention provides a hydrogen exhaust system for a fuel cell vehicle, which can improve the performance and power of the fuel cell stack by supplying water discharged from the fuel cell stack to an air supply line of the fuel cell stack together with purge hydrogen discharged to a hydrogen exhaust line to increase the humidification performance of the fuel cell stack.