The invention belongs to the field of anti corrosive pumps of chemical industry for transferring different fluid mediums, and particularly relates to a titanium nitride nanometer multilayer coating impeller and a preparation process thereof. The basal body material of the impeller is 25 steel, the basal body surface of the impeller is a titanium nitride high hardness coating, and a titanium transition layer is arranged between an impeller basal body and the titanium nitride high hardness coating; The preparation process comprises the following specific processes of: pretreating, cleaning ions, depositing a titanium transition layer, and depositing a surface titanium nitride high hardness layer. The titanium nitride nanometer multilayer coating impeller can keep higher hardness and can be used for simultaneously improving the bonding strength of the tenacity of the coating and a basal body, the impact resistance and wear resistance of the coating are improved, the service life of the impeller is prolonged, the preparation process is easy to control, and the production process is stable and reliable. The impeller prepared by the method is compared with the impeller without the coating, the wear resistance and corrosion-resisting properties are greatly improved, and a titanium nitride nanometer multi-layer coating is broadly used for coatings of different anti corrosive pump impellers.