The surface structure of platinum nanoparticle in a fuel cell is the key factor to determine the catalytic efficiency. In this paper, we apply our recently established condensation potential model [2009 Acta. Phys. Sin. 58 3293; 2009 J. Chem. Phys. 130 164711] to predict the surface structure of platinum nanoparticle, and the reliability of the model is verified by molecular dynamics simulations. By first-principles calculations based on this model, we show that for various shapes of platinum particles the surfaces are mainly composed of fcc (111) facets (about 80%), and the ratio of (100) faces is about 10%. The results are consistent with existing experimental observations. Owing to the simplicity of the calculations, this condensation potential model is widely used to predict the surface structure of common nanoparticles.