Spectroscopic properties of SrAl12O19:Pr3+ and Y3Al5O12:Pr3+ have been studied under vacuum ultraviolet excitation at 20, 77 and 300K. Self-trapped exciton(STE) luminescence in these aluminates were observed besides the characteristic emissions of Pr3+. Furthermore, the emission of STE became dominant as the concentration of activators and temperature decreased. The influence of STE on the luminescence of Pr3+ in aluminates was also emphasized.