Abstract: In order to solve the problem of designing and selecting components for 100 kW hydrogen fuel cell systems, a 120 kW hydrogen fuel cell system was designed. The design and calculation of air supply system, hydrogen supply system and cooling system were performed, and system integration was carried out according to relevant provisions of GB/T 24554-2022 "Performance Test Methods for Fuel Cell System" for the 120 kW hydrogen fuel cell system, which was subjected to room temperature idling startup tests, rated power tests, steady state characteristic tests and dynamic response tests. The results show that the rated power of the system reaches 120 kW with good stability of high power output. The efficiency of the system under the rated power is 42.5%, and the efficiency reaches up to 58.5%, which makes the system more practical. This study provides theoretical references for further study of 100 kW hydrogen fuel cell system integration and accelerates the development and application of hydrogen fuel cell automobiles.