The invention belongs to the technical field of biological fermentation, and discloses an anaerobic digestion system capable of improving biogas production efficiency. The anaerobic digestion system comprises an anaerobic digester, a biogas pressure regulating tank, an anaerobic membrane separator and a solid-liquid separator, wherein the anaerobic digester communicates with a feed pipe, a digester flexible gas storage bag, a discharge pipe, a material distribution pipe and a slag discharge pipe, the digester flexible gas storage bag communicates with a digester exhaust pipe, the biogas pressure regulating tank communicates with a biogas discharge pipe and a biogas backwashing pipe, the solid-liquid separator communicates with a biogas residue pipe, a biogas slurry pipe and a coagulant adding tank, the anaerobic membrane separator communicates with a membrane separator flexible gas storage bag, an overflow pipe, a sludge return pipe, a membrane assembly and a side stirrer, and the membrane assembly communicates with a water outlet pipe. The system of the invention overcomes the problems that digestion treatment on organic materials is incomplete, efficiency is low, operation energy consumption is high, and sulfur components in biogas are not treated independently in the prior art, and is suitable for anaerobic digestion of agricultural waste organic materials to produce biogas.