Ba4Sm9.33Ti18O54 (BST) ceramics were prepared by conventional solid-state reaction method. The effect of CuO-Bi2O3 co-doping on the sintering behavior and microwave dielectric properties of BST ceramics has been investigated. The results indicated that when the total addition of CuO-Bi2O3 doping agent was 1.0wt%, the sintering temperature of BST ceramics was reduced to 1240°C as a result of liquid-phase sintering effect derived from CuBi2O4. When the total addition of CuO-Bi2O3 was fixed at 1.0wt%, the microwave dielelctric properties of BST were improved by adjusting the mass percentage of Bi2O3. With the increase of Bi2O3 amount from 20wt% to 80wt%, the dielectric constant (εr) decreased, the quality factor (Q•f) increased and the temperature coefficient of resonant frequency (τf) shifted from negative value to positive value. The excellent microwave dielectric properties of εr=82.51, Q•f=7878GHz and τf=+6.02ppm/ were obtained for the sample with Bi2O3 amount of 80wt% when sintered at 1240°C for 3h.