A paper feeding device is characterized by comprising a slide block, a linear guide rail, an adjusting support plate, a paper feeding cutter, an adjusting bolt, a spring and an adjusting seat, wherein the linear guide rail is connected with the paper feeding cutter, the slide block is fixedly connected with the adjusting seat, or the linear guide rail is connected with the adjusting seat, the slide block is fixedly connected with the paper feeding cutter, the slide block and the linear guide rail are in clearance fit, the adjusting bolt is in threaded fit with the upper part of the adjusting seat, the spring is sleeved on the adjusting bolt and mounted between the adjusting support plate and the adjusting seat, and the adjusting support plate is fixedly connected with the paper feeding cutter. The work method of the paper feeding device comprises the following steps: 1, adjusting paper feeding cutter downwards, rotating the adjusting bolt, moving the paper feeding cutter downwards, and adjusting properly; and 2, adjusting the paper feeding cutter upwards, reversely rotating the adjusting bolt, moving the paper feeding cutter upwards and adjusting properly. The paper feeding device has the advantages as follows: the working end surface of the paper feeding cutter head is circular arc-shaped, so that the quality rate is improved; the thickness of the paper feeding cutter is increased, and the phenomena of double paper pieces are reduced; and by using a linear guide rail pair, the adjusting is convenient, and the actions are smooth.