The novel K6Ba4B8O19∶x%Eu 3+ fluorescent powders are prepared by the solid phase reaction method and their fluorescence quantum efficiency is measured. The results indicate that the nearly pure phase of K6Ba4B8O19 matrix is synthesized experimentally. When the synthesis temperature is 750 ℃, the X-ray diffraction spectrum of K6Ba4B8O19∶5%Eu 3+ is well consistent with that in the standard card of K6Ba4B8O19. Under an excitation at 395 nm wavelength, the orange and the red emission peaks occur at 592 nm ( 5D0F1) and 613 nm ( 5D0F2) of K6Ba4B8O19∶Eu 3+, respectively. The fluorescence emission intensity increases with the increase of Eu 3+ mole fraction, and reaches the maximum when the mole fraction of Eu 3+ is 6%. The fluorescence quantum efficiency of K6Ba4B8O19∶6%Eu 3+ under an excitation at 395 nm is 4.51%. The obtained powders are irregularly granular.