Pr3+ 1 and 5% doped KY3F10 (Pr:KYF) scintillators were prepared by Tokuyama to examine optical and scintillation characteristics. In X-ray induced radioluminescence spectra, Pr3+ 5d-4f emission at 280nm and 4f-4f emission with several lines at visible wavelength were observed. In pulse height measurements with PMT R7600-200, 241Am 5.5 MeV α-ray was irradiated to samples. As a result, Pr 1 and 5% doped KYF exhibited 700 and 300 photons/5.5 MeV-α, respectively. The fast component of the scintillation decay time constants turned out to be 4.5 and 2.5ns for Pr 1 and Pr 5% doped samples, respectively.