Crystallization behaviors of Al–Ni–La amorphous alloys with a fixed Ni (La) content of 6at.% were investigated by X-ray diffraction and differential scanning calorimeter when the La (Ni) content changes from 3 to 9at.%. The results show that the thermal stability of the amorphous alloys monotonically increases with increasing the La (Ni) content. Glass transition only exists in the alloys with the La (Ni) content higher than 6at.%. La plays a more significant role than Ni in promoting the glass-forming ability, improving the thermal stability, stabilizing the supercooled liquid region, depressing the precipitation of fcc-Al in the first crystallization process and increasing the apparent activation energy of the first reaction.