Bismuth has an important promotion effect on the catalytic performance of Pt-catalyzed oxidation reactions. Herein, the catalyst structure, Bi content, and catalytic performance of Bimodified Pt catalysts in the electro-oxidation of glycerol and formic acid were researched to unravel the essential promotion role of Bi. The Bi-modification methods included the loading, adsorption, and electrodeposition of Bi on Pt. The electrodeposited Bi-modified Pt had the best performance among the three methods. In a certain range, the lower electrodeposition potential of Bi resulted in a higher Bi content on the Pt catalyst and better performance. The activity of the Pt catalyst with Bi deposited at À 0.15 V was 8.5 times and 27 times that of the monometallic Pt catalyst in the electro-oxidation of glycerol and formic acid, respectively. The selective distribution of Bi adjacent to Pt and a higher percentage of Bi hydroxide were favorable for the catalytic performance.[a] Dr.