The model is based on and modified from ‟Anaerobic Digestion Model No.1” (ADM1), calibrated and validated by operational data taken from a fullscale plant. Results show that 1) the methane yield enhancement depends on the acceleration of hydrolysis rates as well as the reduction of inert materials, 2) reduction of the hydraulic retention time of digestion can be realized by the acceleration of methanogenesis and the composition control of substrates. The process design combined with the detailed reaction analysis shows that the reduction of the biogas manufacturing cost can be realized by the introduction of pretreatment, the recirculation of effluent solid materials, and the high-solids digestion.