In this paper, we have studied the emission spectra from the thermally excited 3P1 and 1I6 states in SrAl12O19∶Pr3+.The ratio of the emission intensities of 3P1→3H5 and 3P0→3H5 transitions is applied to measure temperature. It is also pointed out that the thermally excited 1I6 emission plays an important role in decreasing the quantum efficiency of the 3P0 visible emission.