The invention discloses an imidazole polyarylamine metal corrosion inhibitor as well as a preparation method and application thereof. The invention discloses imidazole polyarylamine. The structural formula of the imidazole polyarylamine is shown in the specification. The imidazole polyarylamine can be applied to the field of preparation of metal corrosion inhibitors or metal corrosion prevention.The preparation method for the imidazole polyarylamine metal corrosion inhibitor comprises the following step that a hybrid reaction system containing imidazole, benzaldehyde, aniline and an organic solvent is subjected to Mannich reaction in a protective atmosphere at 85-110 DEG C for 1-5 hours so as to obtain the imidazole polyarylamine metal corrosion inhibitor. The imidazole polyarylamine metal corrosion inhibitor has the advantages of being good in water solubility and excellent in corrosion inhibition effect and has good corrosion inhibition performance on carbon steel in a pickling solution. The preparation method is simple, the range of sources of raw materials is wide, the usage amount is small, and the method is suitable for large-scale production. Meanwhile, the application method is simple, a hydrochloric acid solution is added to serve as cleaning fluid so as to perform acid picking on the carbon steel, and therefore the corrosion of the carbon steel in the acid liquid canbe effectively inhibited, and the corrosion inhibition rate of the carbon steel is high.