Relaxor-type ferroelectric perovskites (Ba,La)(Mg,Nb)O3 (BLMN) ceramics have been synthesized from oxides by sintering in airs using a conventional mixed oxide process.From the XRD patterns, it is found that the amount of the perovskite phase increases with the increasing amount of La2O3.Furthermore, by the X-ray photoelectron spectroscopy (XPS) analyzation, it is discovered that the amount of Nb4+ is increased as La2O3 dopants increase from 0 to 0.04.Microwave properties of ceramics was also discusses in relation to the microstructure and density.