A novel blue-emitting double-phosphate phosphor Cs0.72Ca0.72Gd1.28(PO4)2:Eu(2+) was synthesized by the sol-gel method, and the structure and luminescence properties were investigated in detail. The crystal structure and chemical composition of Cs0.72Ca0.72Gd1.28(PO4)2 matrix was analyzed and determined based on Rietveld refinements and phase and chemical composition analysis. The composition-optimized Cs0.72Ca0.72Gd1.28(PO4)2:Eu(2+) exhibited strong blue light, peaking at 462 nm upon excitation at 365 nm with the CIE coordinates of (0.139, 0.091). The quenching concentration of Eu(2+) in the Cs0.72Ca0.72Gd1.28(PO4)2 phase was about 0.01 and attributed to the dipole-quadrupole interaction. The thermally stable luminescence properties, fluorescence decay curves and diffuse reflectance spectra of Cs0.72Ca0.72Gd1.28(PO4)2:Eu(2+) phosphors are also discussed, all of which indicate that the Cs0.72Ca0.72Gd1.28(PO4)2:Eu(2+) phosphor is a promising phosphor for application in white-light UV LEDs.