To promote hydrogen production of immobilized photosynthetic bacteria, an annular fiber-illuminating bioreactor (AFIBR) for biofilm formation on the surface of side-glowing optical fiber was developed. Mathematical model on coupled mass transport processes of substrate transport and biodegradation within biofilm with substrate diffusion and convection within bulk flow region during continuous hydrogen production was proposed. Effects of mass transfer on performance of substrate bio-degradation were investigated. 10 g/L inlet substrate concentration and 100 mL/h flow rate were identified to be Optimum conditions for maximal substrate degradation in the bioreator.