Microstructure and dielectric properties of ZnO-doped (1-8 mol%) 95P(Mg1/3 Nb2/3) O3+5PbTiO3(95PMN+5PT) ceramics were investigated. From SEM analysis it was found that second phases were observed in all the specimens doped with ZnO and the amount of second phases increased with ZnO content. Pb Mg, Nb Ti and Zn were detected in the second phase by EDS. Lattice parameter and diffuseness parameter increased with ZnO content and Tmax(temperature at which dielectric constant is maximum) shifted to higher temperature with ZnO content. These experimental results indicate that some of Zn2- added were incorporated in amorphous phase and the rest substituted Mg2+ Substitution of Zn2- for Mg2- is thought to enhance the formation of microdomain(Mg/Nb=1) of short-range order and this colud be explained by the fact that ionic size difference between Zn2+ and Nb5+ is larger than that between Mg2+ and Nb5- The highest dielectric contric constant was achieved in specimen with 2 mol% ZnO content sintered at 90$0^{circ}C$ for 2 hours. The specimen thous prepared had a resistivity of2$ imes$1011 $Omega$.cm