The present invention provides a microbial hydrogen-producing process, comprising: providing at least one Clostridium microbe and at least one Bacillus microbe; and co-culturing said at least one Clostridium microbe and said at least one Bacillus microbe in a fermentation culture system to produce hydrogen. The present invention also provides a microbial hydrogen-producing system, characterized by that the system comprises at least one Clostridium microbe and at least one Bacillus microbe, and it uses an organic waste medium as the substrate to perform a hydrogen-producing fermentation having high efficiency, high stability, and high reproducibility.