The microwave dielectric properties and microstructure of BaTi4.3ZnyO9.6+y+0.02 mol% SnO2+0.01 mol% MnCO3+x mol% Nb2O5(x=0-0.05, y=0-0.08) system ceramics were studied as a function of the amount of ZnO and Nb2O5 doped. Addition of (y=0-0.05) ZnO and (x=0-0.025) Nb2O5 enhanced the reactivity and decreased the sintering temperature effectively. It also increased the dielectric constant εr and quality factor Q(=1/tan δ) of the system due to the substitution of Ti4+ ions with incorporating Zn2+ and Nb5+ ions, which was analyzed by the reaction ZnO+Nb2O5+3 TiTiX→ZnTi+2NbTi+3TiO2. When the system doped with (y=0.05) ZnO and (x=0.025) Nb2O5 were sintered at 1 160 ℃ for 6 h, the εr, Qfo value and τf were 36.5, 42 000 GHz, and+1.8 ppm/℃, respectively, at 5 GHz.