The invention discloses a composite filter membrane of a biosensor. The composite filter membrane is loaded in the electrode surface of the biosensor, and structurally comprises a biocompatible hydrophilic layer, a porous support layer, an analyte filter layer, a bioactive functional layer and a graphene derivative layer successively from outside to inside. The graphene derivative layer loaded onan electrode can improve the enzyme loading rate and reduce interference of toxic substances seeping from the electrode on the bioactive functional layer; the analyte filter layer improves the detection linear range of the sensor and prolongs the service life of the bioactive functional layer; the porous support layer increases the mechanical strength of the membrane and prevents the bioactive functional layer from being extruded; the biocompatibility is improved by the biocompatibility hydrophilic layer; due to the multi-layer composite structure of the composite filter membrane and selectionof surface functional groups and chain segments among the layers, the affinity among the composite layers is improved, the service life of the biosensor is prolonged, the cytotoxicity of the membraneis reduced, the biocompatibility is improved, and the service life is prolonged.