Carboxymethyl chitosan/Cu composite, carboxymethyl chitosan/Ag composite and chitosan/polyaniline/Pd composite modified electrodes were prepared through in situ electrodeposition. The resultant metal particles were uniformly dispersed in the polymer films. The three electrodes showed good analytic performances to H2O2 with the linear H2O2 concentration ranges of1.0mol/L~10.0mmol/L,10mol/L~6.0mmol/L,10mol /L~7.0 mmol/L, the related coefficients corresponding to 0.999 7, 0.999 9 and 0.999 8, the sensitivities corresponding to 33, 37 and 46 μA·L·mmol -1 ·cm -2 , and the detection limits corresponding to 1 μmol/L, 1 nmol/L and 1 μmol/L, respectively.