Eu2+ and Mn2+ co-activated Sr5(PO 4)3Cl phosphors with blue and orange color double emission bands, under a broad-band excitation wavelength range of 340-400 nm, were synthesized by the solid-state reaction. It was found that the processing parameters, including the fluxes, annealing time and activators concentrations, affect the emission intensity and other luminescent properties. Energy transfer between Eu2+ and Mn2+ was discovered and the transfer efficiency was also estimated based on relative intensities of Eu2+ and Mn2+ emission. Thus the relative strength of blue and orange emission intensities could be tuned by varying the relative concentration of Eu2+ and Mn2+. Since the photoluminescence excitation spectra of the newly developed Sr5(PO4) 3Cl:Eu2+, Mn2+ phosphors exhibit a strong absorption in the range of 340-400 nm, they are promising for producing UV-LED-based white LEDs.