The CaAl12O19∶xMn4+ phosphor was rapidly synthesized at low temperatures with combustion method with urea as combustion agent. The influence of calcination temperature and time, the doping amount of Mn4+ ions, the molar ratio of combustion agent to CaAl12O19, on luminous intensity of fluorescent powder were examined with orthogonal analytical method. The optimum conditions for preparing phosphors are: sintering temperature 1 200 ℃, the amount of Mn4+ 0.02, the molar ratio of combustion agent to CaAl12O19 50∶1, and sintering time 5 hrs. The corresponding luminous intensity of this powder was 95.8, which is the largest. The phosphor shows a strong red luminescence at the 643 and 656 nm due to the 2E—4A2 transition of the Mn4+. The maximum excitation peak was at 470 nm due to the 4A2—4T2 transition of Mn4+ ligand field. The 470 nm excitation peak was matched with the 465 nm emission of the LED chips.