The morphology, microhardness, microstructure, thermal stability, particle size distribution and phase composition of the gas atomized Al₈₆Ni₆Y_4.5Co₂La_1.5 amorphous alloy powder were investigated by scanning electron microscope(SEM), X-ray diffractometry, X-ray Photoelectron Spectroscopy(XPS), particle size analysis, differential scanning calorimetry (DSC), and hardness tester. The result showed that the most size of Al₈₆Ni₆Y_4.5Co₂La_1.5 amorphous alloy powder was smaller 45μm(about 80%), and the structure the powder was consisted of amorphous matrix and nano-crystallization phase. Its crystallization process was amorphous→amorphous′+fcc-Al→fcc-Al+AlNiY+Al₂Y. There existed layer of Al₂O₃ oxidation with width of 180.81nm. The hardness of the powder was beyond 300HV_0.1.