Preparation system and preparation method of solid engine grain

The embodiment of the invention provides a preparation system and a preparation method of a solid engine grain. The preparation system comprises a vibration device; a mixing and forming device which comprises a vacuum tank and a cover plate, wherein the vacuum tank is fixed on the vibration device, and the cover plate is provided with air holes; and a solid engine used for being fixed in the vacuum tank, wherein an opening of a combustion chamber of the solid engine faces upwards, and the cover plate is used for dividing the space of the combustion chamber of the solid engine in the vacuum tank. The combustion chamber of the solid engine is used as a container for mixing grain raw materials and forming grains, and the air holes are used for vacuumizing the vacuum tank in the forming process, so that bubbles among the grain raw materials enter the vacuum tank through the air holes and then are pumped away; the vibration device is used for providing vibration in the grain raw material mixing and grain forming p