Thin films of single c-domain/single crystal (1-x)Pb(Mg1/3Nb2/3)O3－xPbTiO3 (PMN-PT), x≅0.33 near a morphotropic boundary (MPB) composition, were heteroepitaxially grown on (110)SRO/(001)Pt/(001)MgO substrates by magnetron sputtering. The heteroepitaxial growth was achieved by rf-magneron sputtering at the substrate temperature of 600oC. After sputtering deposition, the sputtered films were quenched from 600oC to room temperature in atmospheric air. The quenching enhanced the heteroepitaxial growth of the stress reduced single c-domain/single crystal PMN-PT thin films. Their electromechanical coupling factor kt measured by a resonance spectrum method was 45% at resonant frequency of 1.3GHz with phase velocity of 5500 to 6000m/s for the film thickness of 2.3μm. The d33 and d31 were 194pC/N and –104pC/N, respectively. The observed kt , d33 ,and d31were almost the same to the bulk single crystal values.