Vacuum mixer can mix raw materials and auxiliary materials under vacuum, reduce air bubbles in the materials and increase the elasticity of the products. The mixing shaft is designed as double twisted structure, equipped with inclined paddle and propeller mixing ring, which can make the material do front and back circular motion at the same time during the rotation process, so that the material can be quickly and evenly stirred, fully expanded without air bubbles, with good elasticity, bright color, maximize the extraction of proteins, and lay a good foundation for the next processing procedure.