BaCu(B2O5) (BCB) powder was prepared using BaO,CuO and B2O3 as the main materials. Microwave dielectric ceramics of tungsten–bronze-type BaSm2Ti4O12 (BST) were prepared by doping BCB as the sintering aid. The amount of BCB was varied from 1.0 to 10.0wt.%. The microstructure and dielectric properties of BST were investigated. The sintering temperature of BST ceramics with 6.0wt.% BCB addition can be effectively reduced to 900 oC, about 450 oC lower than that of pure BST ceramics. Good microwave dielectric properties of εr = 62.38, Q×f = 4573 GHz and τf = -27.65 ppm/ oC were achieved.