The invention discloses a method for preparing 6-aminocapronitrile from cyclohexanone-oxime. The method comprises the following steps: carrying out a rearrangement reaction on cyclohexanone-oxime to obtain a rearranged reaction material; and treating the rearranged reaction material to obtain caprolactam, carrying out an ammoniation dehydration reaction on the caprolactam to obtain an ammoniated dehydrated reaction material, and performing separation to obtain the 6-aminocapronitrile. Compared with the prior art, the method of the invention reduces complex separation and refining processes such as back extraction, ion exchange, hydrogenation, evaporation and distillation required after liquid phase rearrangement of the cyclohexanone-oxime, reduces the processes of crystallization, solventrefining and recovery needed after gas phase rearrangement, and organically combines the caproamide evaporation and rearrangement treatment processes in the ammoniation dehydration reaction process. The steam consumption can be reduced by 2.0-3.0 t / t 6-aminocapronitrile, and the cyclohexanone-oxime consumption is reduced by 20-50 kg / t 6-aminocapronitrile.