The invention belongs to the technical field of tobacco microorganism fermentation, and particularly relates to a bacillus subtilis XC-19-1 strain for degrading cellulose in tobacco and application of the strain to tobacco fermentation. The strain is bacillus subtilis XC-19-1, and is preserved in the China Center for Type Culture Collection (CCTCC) in Wuhan with the preservation number of CCTCC NO: M 2017351. The technical scheme of relatively simple and convenient tobacco treatment with an inoculant is designed by specific strain screening, so that the strain has the technical advantages that a technological process is relatively simple and convenient; the treatment cost of the tobacco is lower; the treatment cycle is shorter; and the content of the cellulose in the tobacco can be obviously reduced. Therefore, the strain has better popularization and application values in the technical field of cigarette manufacturing.