The present disclosure relates to an RNAi agent targeting a mitochondrial amidoxime reducing component 1 (MARC1) gene and a use thereof, specifically, the present disclosure relates an RNAi agent including an antisense strand having sequence complementarity to a MARC1 mRNA sequence and a sense strand having sequence complementarity to the antisense strand, and a pharmaceutical composition including the RNAi agent for preventing or treating liver disease, such as non-alcoholic fatty liver disease.