RE-52A rotary evaporator is developed by applying the principle of constant temperature heating and thin film evaporation under vacuum and negative pressure. The instrument is controlled by imported high-grade frequency converter. Stepless speed regulation makes the glass rotary bottle rotate at constant speed. Material forms a large area of uniform film on the wall of the bottle. Then the rotating bottle is heated uniformly by a controllable constant temperature water bath pot. Under the condition of vacuum extraction, the solvent vapor is evaporated at high speed. The solvent vapor is cooled by a high-efficiency glass double condenser and recycled into the collection bottle. The instrument is also equipped with feeding interface and feeding mechanism to facilitate automatic and continuous operation in the evaporation process.