The present technology provides 3,3-difluoroallylamines or pharmaceutically acceptable salts thereof, preparation processes thereof, pharmaceutical compositions comprising the same, and uses thereof. The 3,3-difluoroallylamines or their pharmaceutically acceptable salts exhibit potent inhibitory activity on VAP-1 and therefore can be usefully applied, e.g., for the treatment and prophylaxis of nonalcoholic hepatosteatosis (NASH).