The invention relates to the technical field of cotton quilt manufacturing and particularly relates to an environment-friendly cotton quilt and a preparation process thereof. The environment-friendlycotton quilt comprises two cotton mixing layers which are symmetrically arranged, one sides of the two cotton mixing layers are sewed together, the other three sides of the two cotton mixing layers are connected together through zippers, and the upper cotton mixing layer sequentially comprises a cotton layer, a down feather layer, a photocatalyst layer and a light storage layer from top to bottom.Light is stored by virtue of the light storage capability of luminous powder, the peculiar smell of bacteria in the cotton quilt and a room can be decomposed by the photocatalyst layer under the stimulation of visible light in the sun or an indoor environment, so that the sanitation of the cotton quilt is guaranteed; and the cotton quilt can be recovered into a use state during sleeping at night,the light is stored by the light storage layer in the daytime, the cotton quilt starts to release faint light at night, and the photocatalyst layer continues to react under the irradiation of fluorescence so as to realize degerming and deodorization, so that the cotton quilt can be in the degerming and deodorization states all day long, and the sanitation of the cotton quilt is guaranteed at anytime.