Abstract: A new kind of high dielectric constant,low dielectric loss microwave ceramics was synthesized based on BaO-Ln₂O₄-TiO₂（BLT）system,where Ln represents double Lansilem elements.Employing the new material,a coaxial monoblock microwave filter was designed and investigated.The filter made The resonators are coupled with a novel structure and the length was λ/4,one end was short circuit.HFSS software was used to simulate the properties of the band-pass filter and results showed that the coaxial filter possessed an excellent band pass properties with its center frequency at 1.83GHz,the band width of 43MHz,the insertion loss of less than 0.5dB and the band pass ripple of being 1.5dB.