Major research on hydrogen production by biophotolysis based on microalgal photosynthesis is reviewed. In recent years the stability and yield of photobiological hydrogen production have been significantly improved, and a number of attractive research results concerning the hydrogen metabolism of marine microalgae and photosynthetic bacteria have been reported. Hydrogen production by biophotolysis based on marine microalgal photosynthesis could be a great potential source of energy. Its use could help to prefect the Earth from greenhouse warming and allow the sustainable development of human activities in harmony with the global environment.