The present invention provides use of penta-substituted tetrahydropyrimidines in preparation of thermo-sensitive fluorescent materials. Said penta-substituted tetrahydropyrimidine compounds have linear temperature dependence of red-edge excitation wavelength (LTDREEW). When different excitation wavelengths are chosen, such compounds present fluorescence color and/or fluorescence intensity on-off switching in different temperature ranges. Also their fluorescence intensity ratios or fluorescence intensities exhibit good linear relation or power function relation to temperature, which can be used as the thermo-sensitive fluorescent materials with high sensitivity and wide temperature range (0-450 K).