Abstract: The influence of light intensity on (Rhodobacter sphaeroides)1.1737-thus hydrogen production was investigated under the condition of pig dejecta wastewater. It turns out that, with the increase of light intensity, the activity of Rhodobacter sphaeroides is getting stronger. When the light instensity is above 1000 lux, its activity can be improved drastically; When it comes to 1600 lux, the rate of hydrogen production reached the biggest value. As to 1200 lux, 1600 lux and 2000 lux, the difference in the amount of hydrogen production is relatively low. It indicates that the influence on activity of hydrogen production would decline if light intensity is increased to a certain degree, the influence on the hydrogen production activity of the bacteria would reduce, so there is no obvious influence on the amount and rate of hydrogen production.