Using a convenient solid-state reaction Ce0.67Tb0.33Mg1-xMnxAl11O19 green phosphors were prepared. The effect of Mn2+ doping on the luminescence properties, energy transfer mechanism, and color gamut under 254 nm excitation were investigated. The energy transfer from (Ce, Tb)(3+) to Mn2+ was found to be due to multipolar interactions of the dipole-quadrupole mechanism from theoretical fitting results. The critical distance was calculated to be 0.797 nm. When the Mn2+ doping content was increased from 0 to 0.12, the energy transfer efficiency (Ce3+, Tb3+ -> Mn2+) gradually increased from 0% to 58%. The Ce0.67Tb0.33Mg0.88Mn0.12Al11O19 sample exhibits 105% of the standard NTSC color gamut. Results indicate that Ce0.67Tb0.33Mg0.88Mn0.12Al11O19 green phosphors can be applied to illumination devices and displays.