In order to improve the charging quality of gun powder, the spiral dosing device in the precision weighing technology of gun powder was studied. Through introducing the mechanical structure and working principle of the spiral dosing device, the mechanics model, velocity model and dosing quantity model of dosing process were established. Through designing the key parameters of the spiral dosing device, the dry rapeseed with similar material properties such as loose density and fluidity was used as the substitute material for the experiment. The experimental results show that the study can improve the design level of engineering problems and provide reference for the design of the gun powder spiral dosing device.