Dy 3+ -doped K 2 GdF 5 single crystals with 10.0mol% have been prepared by hydrothermal condition. The spectra are analyzed in term of the Judd–Ofelt theory, the intensity parameters (Ω λ , λ=2, 4, 6) have been evaluated for Dy 3+ -doped K 2 GdF 5 sample. The electric (S ed ), magnetic (S md ) dipole line strength, radiative (A), and total radiative (A T ) transition probabilities, lifetime (τ R ), branching ratios (β R ) for the excited levels of Dy 3+ doped K 2 GdF 5 crystals were investigated by using the intensity parameters. In addition, the stimulated emission cross-sections (σ λp ) and integrated emission cross-section (Σ if ) have been predicted for the transitions from excited level, 4 F 9/2 , to the 6 H 15/2 , 6 H 13/2 and 6 H 11/2 levels. The energy transfer occurs from Gd 3+ to Dy 3+ , resulting in the additional intense excitation UV-narrow bands for the luminescence of the Dy 3+ ions.