CaAl12O19: xMn4+(x=0.0～0.001 84 mol) red phosphors were prepared by high-temperature solid state method. Different influencing factors, i.e. the doping amount of Mn4+, and sintering temperature, were investigated by the orthogonal experiment design. The optimum conditions for preparing CaAl12O19∶xMn4+ phosphors are: sintering temperature 1 500 ℃, and x=0.014 7 mol. It emits strong deep red light with emission maximal peak at 656 nm, and two shoulder peaks (643 and 666 nm), the corresponding excitation peak is located at 470 nm. The 656 nm emission peak is ascribed to the 2E→4A2 transition, and the shoulder peaks (643 and 666 nm) are attributed to phonon sideband transitions. The 470 nm excitation peak is ascribed to the ligand-field 4A2→4T2 transition (d→d band). Owing to the fact that the excitation peak (470 nm) is near the emission (460 nm) of commercial LED chips, it is quite suitable for red light candidate for LED light resources.