The invention provides a naturally degradable paper-based cotton mulching film and a preparation process thereof, and belongs to the field of the mulching film. The preparation process of the naturally degradable paper-based cotton mulching film comprises the steps of weighing a certain amount of cotton linters subjected to manual impurity removal and waste cotton clothes, carrying steaming, pulping and diluting by adopting the pulping manner of integrated steaming and bleaching, and then adding a dispersant, a softening agent, a wet strengthening agent and the like by an appropriate amount to obtain a suspension in which fibers are evenly distributed; pouring the suspension onto the plain copper wire mesh of a papermaking machine, draining out the moisture to obtain a wet fiber mesh, compressing out the moisture and air of the wet fiber mesh by using an oil press, putting the fiber mesh into a drier for 2min, and carefully stripping to obtain the sample semi-finished product of the paper-based cotton mulching film; next, standing the sample semi-finished product of the paper-based cotton mulching film at the room temperature for 24h, and then sufficiently dipping in a dipping tank in which liquid paraffin is held, and finally, dipping in a 4% PVA (Poly Vinyl Alcohol) gluing liquid, carrying out mangling finishing through a two-dipping two-mangling process, putting the finished sample in an oven at certain temperature for pre-drying for certain time so as to realize sufficient adhesion of the sample, and then drying in air at the room temperature to obtain the cotton mulching film.