With the development of blood glucose monitoring medical devices, higher requirements are put forward for the sensitivity and detection limit of biosensors. Herein, a high-performance flexible enzymatic glucose biosensor was prepared by electrochemical deposition of dendritic gold nanostructure on carbon cloth substrate, then covalently immobilizing glucose oxidase on the dendritic gold, and then increasing enzyme loading by enzyme precipitation coating. The morphology of dendritic gold nanostructures was characterized by scanning electron microscopy (SEM). The electrochemical performance of the biosensor was analyzed by cyclic voltammetry (CV), chronoamperometry curve and electrochemical impedance spectroscopy (EIS). It is found that the obtained biosensor has high sensitivity (72.45 μA∙mM-1∙cm-2), low detection limit (6.7 μM) and ultra-wide linear range (0.02-31.7 mM) for glucose detection. In addition, the biosensor also has good selectivity, reproducibility and stability. In the detection of real serum samples, the biosensor also shows good accuracy and practicality. The results show that the new biosensor has great potential for applications in biomedical and health care.