Biomass briquette is one of the most common energy fuels in some countries. It is essential to achieve the highquality biomass briquette, since the quality has a direct influence on the efficiency of utilization. For the purpose to improve biomass pellet quality, a method of ram compression molding machine on the basis of the numerical control pressure device was conducted. The machine adopted a switched reluctance motor which had high starting torque and can stop/start frequent as a power source. It drived the flywheel by belt drive, then converted the rotary motion of flywheel into the up and down reciprocating motion of the plunger through the screw mechanism. The machine also took the property that flywheel can accumulate energy. The die consisted of three parts, with a structure of “straight-cone-straight”. Any part with different size parameters can be replaced, which can suit for different biomass raw materials. Meanwhile, the lower end of the plunger always reciprocated in the die below the lower edge of the discharge port of the screw feeding device. At the moment, due to the discharge port was blocked, the biomass raw material was precompressed by the continuously screwing helical blade, which improved the subsequent molding efficiency. While working, the plunger would accelerate downwards based on the energy accumulated during the upward and the gravitational potential energy of the slider. Then, the biomass raw materials were compacted and squeezed out. Experiments were carried out with typical biomass raw materials, including corn stalks and sawdust. The results indicated that the molding method had a well feasibility. The briquette was 60mm in diameter and different lengths. All the density of the briquettes was 1.2g/cm3 approximately, the drop resistance index was higher than 95%, and the power consumption was 36.51kW·h/t. All indicators met the requirements of the relevant standards. The proposal of the forming machine can provide reference for the development of biomass densification technology.