Reduction of dioxygen catalyzed by laccase was studied at platinum nanoparticles (PtNPs) modified electrodes. PtNPs with laccase are directly fabricated on glassy carbon electrode (GCE) and indium tin oxide electrode (ITO) by simple process. The PtNPs/laccase modified ITO electrode surface has been studied in detail using atomic force microscopy (AFM). This PtNPs/laccase modified GCE effectively exhibits the electro reduction signals for the detection of oxygen. PtNPs provided large surface area for laccase base on modified electrode. The PtNPs present on the electrode provided electrical connectivity between the electrode and the enzyme active sites. The cyclic voltammetry (CVs) has been used for the measurement of electroanalytical properties of analytes by means of modified electrodes. The stabilities of laccase, the reduction potentials and ratios of catalytic to background currents were compared. The power densities of biofuel cell was 84 W/cm2 at 0.62 V, respectively. The biofuel cell showed highly stable output in long-term performance. Efforts are underway to improve the interface transfer to achieve higher potential and current output.