The present invention discloses a biological membrane filtration wastewater treatment system including a porous biological filtration bed zone and a membrane separation zone. The porous biological filtration bed zone has the dual function of providing biological treatment and higher filtration rates, wherein a fixed bed or moving bed is utilized so that the porous biological filtration bed zone has the advantages of high loading rates, high removal efficiencies, high stability and ease of operation. The membrane separation zone utilizes a membrane filtration module to filter an effluent from the porous biological filtration bed zone, so that solid particles therein are separated and remain in the system. Therefore, a high quality of effluent is obtained.