Double-layer stainless steel reactor is a commonly used biochemical instrument, widely used in modern fine chemical, biopharmaceutical, scientific research and experimental industries. It can be used for concentration, distillation, reflux, separation and purification under constant speed, constant force and constant temperature. It is an ideal instrument for teaching, experiment, pilot and production. Through the interlayer of the double-layer reactor, a constant temperature (high temperature or low temperature) hot solution or coolant is injected to heat or cool the materials in the reactor at a constant temperature, and stirring can be provided. The materials react in the reactor, and the evaporation and reflux of the reaction solution can be controlled. After the reaction is completed, the materials can be discharged from the discharge port at the bottom of the reactor, which is very convenient to operate. It is an ideal equipment for modern chemical samples, petrochemical, sample experiments, biopharmaceuticals and new material synthesis.