In this paper, Nd3+-doped GdTaO4 laser crystal for scintillator with high density is successfully grown by the Czochralski method, and the absorption spectra are measured along the a, b and c directions in a wide wavelength range of 260-2000 nm. The experimental energy levels for Nd3+ are analyzed and identified. The free-ions and crystal-field parameters are fitted by the experimental energy levels with the root mean square deviation of 12.66 cm-1, and 102 Stark energy levels for Nd3+ in GdTaO4 host crystal are assigned. The fitting results of free-ions and crystal-field parameters are compared with those already reported for Nd3+:GdxLu1-xTaO4 (x=0.85) crystal. It indicates that the fitting results of Stark energy levels agree well with the experimental spectra.