The temperature dependences of dielectric properties for [001] PMN-0.32PT single crystal and PMN-0.32PT ceramics under different dcelectric field (E) have been investigated. A new monoclinic phase can be induced by electric field with E=1.5-4.0 kV/cm, while heating, in [001] PMN-0.32PT single crystal. The phase transition process of single crystal is from rhombohedral to monoclinic, then from monoclinicto tetragonal, finally from tetragonal to cubic. With increasing electric field, all of the phase transition temperatures increased in the singlecrystal. Comparing with single crystal, no new phase is induced by electric field and temperature field in PMN-0.32PT ceramics. Similar tosingle crystal, the phase transition temperatures of PMN-0.32PT ceramics increased with increasing electric field. The difference of dielectricresponse under dc electric field between two materials is discussed. The formation of new monoclinic phase results from polarization rotationfrom [111] to [001] direction under electric field in single crystal.