The effects of sintering aids on the microstructures and microwave dielectric properties of SmAlO3 ceramics were investigated. CuO and ZnO were selected as sintering aids to lower the sintering temperature of SmAlO3 ceramics. With the additions, the sintering temperature of SmAlO3 can be effectively reduced from 1650 to 1430degreesC. The crystalline phase exhibited no phase differences at low addition level while Sm4Al2O9 appeared as a second phase as the doping level was over 0.5 wt.%. In spite of the additions, the dielectric constants showed no significant change and ranged 19-21. However. the quality factor Q x f was strongly dependent upon the type and amount of additions. The Q x f values of 51,000 and 41,000 GHz could be obtained at 1430degreesC with 0.25 wt.% CuO and ZnO additions, respectively. The temperature coefficients depended on the additions and varied from -40 to -65 ppm/degreesC. Results of X-ray diffractions, EDS analysis and scanning electron microscopy were also presented.