Uniform shape platinum nanocrystals with narrow size distribution and controlled average dimension are successfully embedded in a polymeric matrix and supported on zeolite Beta. The surface structure and reactivity of nanometalclusters are investigated by TEM, EXAFS, CO adsorption and methane activation. The results indicate that nanometalparticles in PVP-Pt/Beta materials have high surface activity and reactivity to activate methane even at temperature of 373K.