The present invention relates to novel C-glycosyltransferase variants and a use thereof. The C-glycosyltransferase variants according to the present invention have improved glycosidic bond-forming ability as compared with wild-type C-glycosyltransferase, and thus can increase the glycoside production effects of polyketide groups and pseudo-natural products, particularly type I, II, III polyketide, nonribosomal peptides, phenylpropanoids, and other aromatic natural products, and thus can be useful for the preparation of a drug, a food additive, a nutritional supplement, and the like containing a C-glycoside compound as a constituent ingredient.