The invention provides self-adhesive paper and a preparation method thereof. The preparation method of the self-adhesive paper comprises steps as follows: S1), traditional Chinese medicine residue powder, softwood pulp and hardwood pulp are mixed with wood fiber bating enzyme for repulping, then calcium carbonate and a wet strength agent are added, a mixture is stirred and subjected to continuous repulping, and pulp after repulping is obtained; S2), the pulp after repulping is subjected to grinding treatment, and pulp is obtained; S3), the pulp obtained in the S2) is subjected to papermaking and gluing treatment, and the self-adhesive paper is obtained. Compared with the prior art, traditional Chinese medicine residues are directly taken as pulp raw materials to be recycled, the equipment is simple, an incinerator built for a pharmaceutical factory or landfilling is not required, waste is directly changed into treasure, resources and cost are saved, and the problem about treatment of herb residues of large and medium-sized pharmaceutical factories is fundamentally solved.