Abstract: Key instrument was O2 absorber in the controlled atmosphere store.Closed circuit fruits and vegetables preservation O2 elimination device was designed successfully based on introduction，digestion and absorption of foreign advanced technology.With closed circuit working mode，machine was composed of frame，oxygen measuring instrument，molecular separation tank，induced draft fan，vacuum pump，filter and reversing valve，etc.This machine could decrease oxygen concentration and remove carbondioxide in storage of fruits and vegetables.Environments of low oxygen concentration and suitable carbondioxide concentration were beneficial to inhibit the respiration of fruits and vegetables，and that could reduce the loss of nutrients.Meanwhile，that could inhibit the propagation of pathogen and prevent the occurrence of physiological diseases.Machine had the advantages of cheap price，high automation and low energy consumption，its main performance index had reached or exceeded the international advanced level，now it had be used in lots of controlled atmosphere store in China.