Artificial superlattice thin films consisting of two different compositions of Pb(Zr,Ti)O3 (PZT), which are in tetragonal and rhombohedral phases at room temperature in the bulk state, were grown on (111)cSrRuO3/(111)SrTiO3 by pulsed laser deposition. Fairly perfect periodicity with sharp interfaces was observed by X-ray diffraction and scanning transmission electron microscopy. It was found that the film with each layer of 5 nm thickness had a single-domain structure for both PZT layers, which would arise from the strong mechanical and electrical coupling between PZT layers. The fabricated superlattice thin films showed saturated P-E hysteresis curves. Larger electromechanical response was observed in the films with smaller layer thickness.