The lattice Boltzmann method is applied to simulate the fluid flow and mass transfer accompanying biochemical reaction，which is a bio-hydrogen production system by photosynthetic bacteria in biofilm adhered on the surface of tube bundle.The effect of inlet velocity(Reynolds number)，tube spacing and tube arrangement(inline and staggered)on velocity and concentration fields，average drag coefficient，and Sherwood number of substrate are investigated.The velocity field and concentration fields of substrate and product under various conditions are depicted.Lower substrate concentration and higher product concentration are obtained at the rear of tubes，both for inline and staggered arrangement. Compared to that with inline arrangement，the substrate concentration is lower and product concentration is higher at the outlet for solution fluid flow around staggered bundle.Furthermore，the hydrodynamics and mass transfer are estimated by parameters of average drag coefficient and Sherwood number of substrate.The numerical results reveal that small tube spacing leads to high Sherwood number of substrate，but at the expense of high drag coefficient.Compared with inline arrangement，the staggered arrangement leads to an up to double increment in Sherwood number and the increment increases with Re，while drag coefficient increases only 10%.It is concluded that small fluid disturbance has a great impact on the mass transfer，and the staggered arrangement is more beneficial to mass transfer and biodegradation.