NGAB crystal index n o,n e at some specifical wavelengths and its temperature coefficient, which are measuredwith the combination of minimum deviation and fixed incident angle, are reported. Thecrystal dispersion equation is given, and its phase-matching angle at the wavelength 1.064μm iscalculated. More than 5mW of the output power at 0.53μm is obtained from a NGABcrystal with volume 3mm×3mm×5mm, pumped by LD;its light-light conversion efficiency is0.5%, and the output at 1.064μm is 214mW, the conversion efficiency is 26%.