The vacuum drying oven adds vacuum conditions on the basis of high temperature drying, which greatly reduces the boiling point and vapor pressure, provides a dust-free, vortex-free drying process and a mild environment for the test and heating process, and also makes the solvent vapor easy to collect , discharge or reuse. In addition, storage, heating, testing and drying are carried out in an environment without oxygen or full of inert gas, so the test sample is not easily oxidized.