Abstract: The Pd-P/C catalyst with the high content of P⁰ was successfully prepared with the organic impregnation-reduction method. Pd-P/C catalysts with different Pd/P atomic ratios were characterized by X-ray diffraction (XRD), Energy Dispersive X-ray Spectrometer (EDX). The effect of Pd-P/C catalysts with different Pd/P atomic ratios on the oxidation of formic acid was also demonstrated by several electrochemical measures. It was found that the potential of the anodic peak of formic acid at catalyst electrodes increased in the order of Pd₁P₆/C < Pd₁P₈/C < Pd/C, and the electrochemical stability of three electrodes was in the order of Pd₁P₆/C > Pd₁P₈/C > Pd/C. The Pd₁P₆ catalyst showed the best performance for the oxidation of formic acid. The Pd-P/C catalysts with the suitable atomic ratio of Pd and P had higher activity and stability for the oxidation of formic acid.