The invention discloses a catalyst for preparing propionitrile, a method for preparing the catalyst and a method and a device for applying the same. The catalyst comprises a carrier portion and a metal salt portion. The carrier portion is a gamma-aluminum oxide carrier, and the metal salt portion comprises nickel salt, copper salt and zinc salt. Compared with the prior art, the catalyst, the methods and the device have the advantages that the catalyst is high in activity, active component dispersity, acrylonitrile conversion rate and propionitrile selectivity, good in stability and long in service life; technologies for preparing the catalyst are simple, applied catalytic reaction is easy to control, and technologies are relatively simple; the catalyst is low in preparation cost and short in preparation process, is made of inexpensive materials and only has simple equipment requirements.