In the course of circular mould straw briquetting, the entrance of the circular mould is worn very serious due to sliding friction between straw pellet and the circular mould. With a vertical circular mould consisted of H module as the research object, this paper put forward a rolling entrance structure which is made of bearings and roller, and the structure is stationary fitted in round holes of two wings up and down at the waist position of H module closed the feed side. When straw pellet was pressured into the mould hole between adjacent rollers, rolling friction coefficient between rollers and straw pellet was reduced smaller than sliding friction coefficient between the original mould and straw pellet, the purpose of weakening the module wear was achieved. At first, wear rule of the original circular mould before improvement was analyzed by the FEM. The geometric model of the original circular mould consisted of H modules was established in accordance with 9JY2000 straw briquetting machine of a factory, high and wide of the mould hole are 33mm×32mm. Under conditions that elasticity modulus of straw was 8.1GPa, plastic relation of straw was Euler stress and Almansi strain, sliding friction coefficient between the circular mould and straw was 0.4, hardness of the circular mould was HRC55, rotation speed of pressure rollers was 30r/min, temperature was room temperature, straw briquetting was simulated by means of the Archard wear model. The result showed that normal pressure at the front edge of the H module waist was larger, 45MPa, and wear rates of this edge was 0.11μm/s. The second, wear rule of the circular mould of rolling entrance structure after improvement was analyzed by the FEM. Under conditions that diameter of the roller was Φ35mm, friction coefficient between the roller and bearing bush was 0.01, the model of the circular mould of rolling entrance structure was established and simulated by the FEM. The result showed that rollers laid a single direction intermittent rotation, the maximum angular velocity was 0.05rad/s; the maximum normal pressure was 23.7MPa, and the wear rate of this point was 0.01μm/s, which was far less than wear rate before improvement. At last, according to field experiments, the circular mould of rolling entrance structure can play the function of reducing wear and prolong the life of the circular mould.