An amperometric glucose biosensor based on a polymeric cobalt tetraaminophthalocyanine (p-CoTAPc) film coated glassy carbon (GC) electrode was developed. The monomer, Co(II)-4, 9, 16, 23-tetraaminophthalocyanine, was electropolymerized at a glassy carbon electrode for detecting hydrogen peroxide in the presence of oxygen by electrocatalytic oxidation. Glucose oxidase (GOD) was immobilized on the p-CoTAPc film coated glassy carbon electrode by cross-linking with glutaraldehyde for glucose assay and a layer of polyphenol (PPh) film was electropolymerised on the enzyme layer for guaranteeing the permselectivity. The biosensor retains its full activity for at least three months and responds rapidly to glucose with a detection limit of 8×10−6M and a linear concentration range of 1×10−5− 2×10−3M. The polyphenol film can not only prevent interferences from some electroactive species, e.g. ascorbic acid, uric acid and cysteine etc., but also increases the thermal stability of the biosensor. The electrode was successfully applied in clinical analysis of glucose in human blood plasma.