We investigate monolayers of planes (111) of Pt in the FCC structure located on graphene. The energy of formation showed that the most stable structure is √3×√3 — Pt on 2 × 2 — graphene. This system has a mismatch in the lattice constant of 0.45. The layers are completely flat, and its band structure shows that the new structure is metallic and the Dirac's cones are displaced 0.6eV above of the Fermi level. In this work we present the dependence of the enthalpy of formation of these structures and we calculated all structural parameters of their relaxation.