The absorption and emission spectra of Nd3+:GdMgB5O10 crystal were inves- tigated. Based on Judd-Ofelt theory the three parameters of oscillator strength were obtained as follows: Ω2 = 2.099×10-20 cm2, Ω4 = 4.599×10-20 cm2 and Ω6 = 5.139×10-20 cm2. The fluorescence branch rations were also obtained: β1 = 0.424, β2 = 0.474, β3 = 0.094 and β4 = 0.005. The radiative lifetime is 416 μs and quantum efficiency ηc 9.13%. The emission cross section σp (1.06 μm) is 4.38×10-19 cm2.