The utility model relates to a waveguide used for vacuum microwave drying equipment, which can effectively solve the problems that a vacuum chamber is caused, vacuum drop is caused or the needed vacuum cannot be reached due to the bad tightness of the existing microwave waveguide. The utility model adopts a technical scheme as follows: the waveguide used for the vacuum microwave drying equipment comprises a vacuum chamber, and a fixed opening is configured on the vacuum chamber; a base is fixed on the fixed opening by welding, and an opening is configured on the base; the opening is provided with a teflon sealing block; a sealing gasket is arranged between the teflon sealing block and the base; a pressing plate is arranged at the upper part of the base; the pressing plate is provided with a microwave inlet corresponding to the teflon sealing block. The waveguide used for the vacuum microwave drying equipment provided by the utility model has the advantages of novel and unique structure, safe and convenient use, good tightness and capability of effectively reducing the attenuation of the microwave in the waveguide.