AbstractCircular moulds, which have multiple holes, are key components of biomass briquetting machines. The configuration parameters of the die holes determine the strength and the service life of the circular moulds. Special testing moulds were designed for this research, and the strain values of the specific points were detected using strain-gauge transducers. Then, the mechanical data of the points, including the positive pressures and the friction and distribution values, were calculated. Mechanical models were established to explore the stress change of the die holes by altering the rheological properties of the straw. In addition, the mechanical models provided the theoretical principles for analyzing their influence on biomass solidification by changing the forming pressure of the die holes during the biomass briquetting process.