The hydrothermal synthesis digestion tank can be used in the determination of heavy metals such as lead, copper, cadmium, zinc, calcium, manganese, iron, mercury, etc. It can also be used as a high temperature and high pressure resistant anti-corrosion and high purity reaction vessel, as well as in organic synthesis, hydrothermal synthesis, crystal growth or sample digestion and extraction. In sample pre-treatment ablation of heavy metals, sludges, rare earths, aquatic products, organic matter, etc. Therefore, it is widely used in research and production in petrochemical, biomedical, material science, geochemistry, environmental science, food science, commodity inspection and other sectors.