Abstract: In this study, we examine the optical properties of Er3+ ions doped KY3F10 single crystals. After crystal growth and X-ray diffraction analysis, the optical properties of Erbium ions in KY3F10.The measured absorption line strength at room temperature were used to fit the three phenomenological Jud-Ofelt (JO) parameters t(t = 2,4,6).The emission transition probabilities branching ratios and radiative lifetimes are then deduced. The possibility to use such material for laser emissions is discussed.