The effects of LiF as the Li source were investigated on the properties of Fe3+ doped red phosphors. LiF had advantages on leading to different luminescent properties through the different host crystals. Excess LiF promoted the crystallization of metastable α-LiAlO2 up to 800 °C and enhanced the PL of γ-LiAlO2:Fe3+ above 800 °C with the flux effect. The wavelength of the red emission from Fe3+ became shorter in the order of γ-LiAlO2:Fe3+, α-LiAlO2:Fe3+ and Al4LiO6F:Fe3+.