Experiment on the main parameter of biomass pellet mill with corn straw was performed on account of high energy consuming in the process of modeling. Energy consumption per ton solid biofuel, the rate of qualified molded biofuel, mechanical durability and particle density were used to evaluate the effect of changing clearances between rolls and die, spindle speed and diameter of die orifice. The results indicated that clearances between rolls and die justhad an effect on the rate of qualified molded biofuel, and the best optimal value was 02mm, the energy consumption and particle density reducing by increasing of the spindle speed, bigger diameter of die orifice would bring about higher productivity and lower energy consumption. The spindle speed scope should not lower than 160r/min to ensure the high productivity. Further, the rate of qualified molded biofuel was bigger than 95% and mechanical durability was bigger than 96%, which matched the requirements when experiments were done with different factors.