The invention discloses a cotton quilt hemming device, relates to the technical field of fabric hemming equipment, and aims to solve the technical problem that the surface quality of products is reduced after hemming due to wrinkles of cotton quilts. According to the technical scheme, the cotton quilt hemming device comprises a working table, two transverse columns are arranged at one end of the working table, a first flattening roller is arranged between the two transverse columns, a driving piece is arranged at one end of the first flattening roller, and is fixedly connected to the outer side walls of the transverse columns; and a stand column is arranged on the side, facing upwards, of each of the two transverse columns, a second flattening roller is arranged between the stand columns,and when a cotton quilt passes through a space between the first flattening roller and the second flattening roller, the first flattening roller and the second flattening roller rotate to flatten thecotton quilt, so that the surface quality of a product is improved.