It is reported a comparative periodic density functional theory study of the reaction of water dissociation on five platinum surfaces, e.g. Pt(111) Pt(100), Pt(110), Pt(211) and Pt(321). It was found that water molecules adsorb stronger on surfaces presenting low coordinated atoms in the surface. In the cases of the stepped Pt(110) and kinked Pt(321) surfaces, the activation energy barriers for the reaction of water dissociation are smaller than in the other three surfaces studied and are also smaller than the adsorption energies for the water molecule on the corresponding surfaces. Therefore, the calculations suggest that the dissociation reaction will take place preferentially at corner or edge sites with the (110) orientation on platinum particles.