Perovskite lead titanate nanostructures with specific {111}, {100} and {001} facets exposed, have been employed as supports to investigate the crystal facet effect on the growth and CO catalytic activity of Pt nanoparticles. The size, distribution and surface chemical states of Pt on the perovskite supports have been significantly modified, leading to a tailored conversion temperature and catalytic kinetics towards CO catalytic oxidation.