In this paper, the Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3(PMN-PZT) piezoelectric ceramics were prepared by one-step synthesis method. The effect of Sm-doping on the structure and electrical properties of PMN-PZT ceramics were investigated. High piezoelectric performances are achieved in 2.0% (mole fraction) Sm-PMN-PZT ceramics, which are piezoelectric constant d33=611 pC/N, electromechanical coupling coefficient kp=0.68, dielectric loss tan δ=1.65%, relative dielectric constant εr=2 650, along with a high Curie temperature TC=283 ℃. Furthermore, a large unipolar strain of 2.0%Sm-PMN-PZT ceramics is attained to be 0.20% at the electric field of 3 kV/mm, which shows the characteristic of large strain material. These results suggest that the Sm-doped PMN-PZT ceramics with outstanding comprehensive properties are promising in the field of transducers, sensors, actuators, etc.