A novel photoelectrochemical biosensor incorporating nanosized CdS semiconductor crystals with enzyme to enhance photochemical reaction has been investigated. CdS nanoparticles were synthesized by using dendrimer PAMAM as inner templates. The CdS nanoparticles and glucose oxidase （GOD） were immobilized on Pt electrode via layer-by-layer （LbL） technique to fabricate a biological-inorganic hybrid system. Under ultraviolet light, the photo-effect of the CdS nanoparticles showed enhancement of the biosensor to detect glucose. Pt nanoparticles were mixed into the Nation film to immobilize the CdS/enzyme composites and to improve the charge transfer of the hybrid. Experimental results demonstrate the desirable characteristics of this biosensing system, e,g. a sensitivity of 1.83 μA/（mM cm^2）, lower detection limit （1 μM）, and acceptable reproducibility and stability,
