Pt catalysts supported on lignin-based carbon dots are successfully prepared, and their catalytic performances for methanol electro-oxidation are investigated. Firstly, lignin-based carbon dots (Lg-CDs) are prepared by the acid etching of lignin carbonization products. Then, Pt catalysts supported on lignin-based carbon dots (Pt/Lg-CDs) are synthesized by the reduction of chloroplatinic acid in carbon dots solution. Although Pt/Lg-CDs catalysts aggregate obviously due to the deposition of Pt catalysts on the surface of Lg-CDs, the activity and stability of an optimal Pt/Lg-CDs-800 catalyst are still more outstanding than commercial Pt/C (40%Pt) and PtRu/C (30%Pt+15%Ru) catalysts for methanol electro-oxidation reaction (MOR) in acidic solutions. A large number of oxygen-containing groups on the surface of Lg-CDs-800 facilitate the uniform and stable deposition of Pt catalysts, and make the surface of more Pt catalysts expose to reaction system, thereby improving catalytic performance.