Abstract: The anisotropy absorption spectroscopy of crystal for 3-axis Nm, Ng, Np were conducted at room temperature. The characteristics of spectroscopy were analyzed and compared. The energy level transition of the absorption cross-sections was calculated. The strongest absorption and biggest absorption cross section parallel to the Np principal axis, which increases the number of accumulation for particles, the transition probability and the fluorescence output. The Yb3+-doped leads to a strong absorption and large half width near 980nm. Under 980nm LD excitation, the up-conversion green and red luminescence was achieved. There is little difference in peak for the up-conversion luminescence of 3-axis Nm, Ng, Np, in which Np is the strongest in the three axes.