The double cone rotary vacuum drying machine is communicated with the heat energy source (such as hot water, low pressure steam or heat conduction oil) in the closed interlayer. The material is in a vacuum state, the vapor pressure drop causes the material surface water (the solvent) to reach the saturated state, and the vacuum pump is discharged in time. Internal water (solvent) to the surface of the continuous infiltration, evaporation, discharge three processes, the material in a very short period of time to achieve the purpose of drying.