The present invention relates to a crystal form of 3-(4-methyl-1H-imidazol-1-yl)-5-trifluoromethylaniline monohydrochloride and the use thereof. Specifically, disclosed are a crystal form A of a monohydrochloride anhydrous substance of 3-(4-methyl-1H-imidazol-1-yl)-5-trifluoromethylaniline monohydrochloride, a method for preparing the crystal form A and the use of the crystal form in the synthesis of nilotinib. The crystal form A of the present invention has good stability and purity, and can be directly used in the preparation and production of nilotinib. The method for preparing nilotinib in the present invention is easy to operate and has high industrial application value.