A system and method for supplying hydrogen gas, and a hydrogen fuel cell system are provided to solve inconvenience caused by the requirement for replacing a hydrogen storage container during hydrogen gas supplement. The system for supplying hydrogen gas includes a hydrogen storage unit, a hydrogen conveying unit and a charging device connected to the hydrogen storage unit, where the charging device includes a charging opening matched with a hydrogen gas infusing unit. It may be noted that according to the solution provided by the embodiments of the present disclosure, when hydrogen gas needs to be supplemented, an external infusing device may be used to infuse hydrogen gas to the hydrogen storage container in the hydrogen storage unit through the charging opening, which avoids replacement of the hydrogen storage container during an entire infusing process, and makes an intensive hydrogen gas supplement process more convenient and faster.