A 1, 2-dihydro-1, 6-naphthyridine derivative, a preparation method therefor, and an application thereof in medicine. Specifically provided are a 1, 2-dihydro-1, 6-naphthyridine derivative as represented by formula (I), a preparation method therefor, pharmaceutically acceptable salts thereof, and application thereof as therapeutic agents, particularly c-KIT inhibitors, wherein the definitions of the substituents in the formula (I) are the same as the definitions in the description.