Bi3+ doped YBO3 phosphors are prepared by solid state reaction and their luminescent properties are invest gated by using synchrotron radiation instrument.Concentration and temperature dependences of YBO3:Bi3+luminescence under VUV/UV excitation is observed.The emission and excitation spectra are assigned,and th mechanism for these phenomena is explored,which result from the energy transfer between Bi3+ ions occupyin different sites in YB03 crystal lattice.