Pin broken appears in process of extrusion of 19-hole propellant and products are hard to be shaped when the viscosity of flow is high. This study simulated the forming process of propellant by the finite element method to solve this problem. On the basis of simulation results, effects of the compression ratio, the length of forming section and structure of pin holder on the distribution of stress and velocity of propellant flow were analyzed. The compression ratio of the optimized die is 4.25, the forming length is 26.0 mm, and the pin holder is optimized to increase the axial flow propellant. The results show that, after optimization, the maximum pressure in the flow channel reduces by 40.45%, the radial force on the outermost die pins reduces by 37.45%, the maximum radial velocity of the fluid in compression section decreases by 66.98%. The components distribute evenly, the propellant surfaces are smooth and the holes are in good distribution in propellants which are extruded by the new die. The constant volume combustion experiment confirms that the 19-hole propellants burn stability and the progressive combustion is excellent.