The microstructural changes originated from Cr doping in 0.2PZN-0.8PZT piezoelectric ceramics were investigated by means of XRD and Raman scatteringl The phase transition from rhombohedral to tetragonal and the increase of crystal tetragonallity are caused by Cr addition. The studies about the lattice parameters and the phase transition through Raman scattering are confirmed by XRD. So, the microstructural changes induced by doping in the piezoelectric ceramics with tetragonal and rhombohedral structures simultaneously can be revealed through the analysis of the Raman vibration modes in different structures.