The effect of AlF3 concentration on the microstructures and energy storage properties of barium strontium titanate glass ceramics was studied. Scanning electron microscopy investigations revealed that the addition of AlF3 significantly changed the microstructure morphology of the glass ceramics. Dielectric measurements indicated that the dielectric constant has a maximum value at 2 mol% AlF3 concentration. Using polarization-electric field measurements, the energy storage properties were found to be influenced strongly by the AlF3 concentration. The correlation between the microstructure and the dielectric property in the barium strontium titanate glass ceramics with different AlF3 concentrations was qualitatively discussed.