AY2Si3O10 (A=Sr, Ba) trisilicate ceramics were synthesized by traditional high temperature solid state reaction method. X-ray diffraction patterns and Rietveld refinement revealed that AY2Si3O10 (A=Sr, Ba) ceramics belonged to triclinic and monoclinic crystal systems with P and P21/m space groups, respectively. The vibrational modes of [SiO4] tetrahedra, [YO6] octahedra and [(Sr/Ba)O8] polyhedra were analyzed by Raman spectroscopy. The infrared spectroscopy fitting analysis was used to determine intrinsic dielectric properties. Excellent microwave dielectric properties were measured for SrY2Si3O10 and BaY2Si3O10 with r = 9.