In this study, we suggested an integrated humidification system for a fuel cell electric vehicle (FCEV) as an efficient method of humidification under the various driving condition of the fuel cell vehicle and system. It is improving air humidification system combined the existing membrane humidifier and water injection. As a result, we verified it through experiments and the vehicle test and could get a result of improvement of humidification performance. The results show that an integrated humidification system is a useful method for FCEV applications.