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The K 2 SiF 6 :Mn 4+ phosphor was synthesized by a redox reaction from SiO 2 [1]. Under the 450 nm excitation, K 2 SiF 6 :Mn 4+ show a narrow deep-red emitting around 633 nm which attributed to the 2 E g to 4 A 2g transition of Mn 4+ ion with the half width of 8 -10 nm. The particle size was approximately 8 ㎛. We obtained single phase of cubic structure with a space group of Fm-3m (225) which agree with XRD pattern of JCPDS # 85-1382. In the temperature dependence of emission spectra, emission intensity decrease to around 60 % (80 %@200 YAG) of that at room temperature is about 175 . The chemical stability of the phosphors was improved by coating the phosphor with target metal oxide. These phosphors can be efficiently excited by the blue light-emitting InGaN diode and provides a high color rendering property with green or yellow phosphors. It will be useful as a red phosphor for white-light-emitting diode.