After fresh fruits and vegetables are packaged in plastic film, the respiratory activity of fruits and vegetables consumes oxygen and produces about the same amount of carbon dioxide, gradually forming a gas concentration difference between the package and the atmosphere. The oxygen in the atmosphere penetrates through the plastic film to supplement the oxygen consumed by the respiration of fruits and vegetables. The excess carbon dioxide generated by the respiration of fruits and vegetables in the package will seep out of the plastic film and diffuse into the atmosphere. At the beginning, the difference in concentration of gas inside and outside the package is small, and oxygen infiltrated into the package is not enough to offset the consumed oxygen, and the carbon dioxide that is leached out is smaller than the carbon dioxide produced. With the increase in the concentration of gas inside and outside the packaging during the storage process, the gas permeation rate increases, but the oxygen consumption rate in the package is equal to the oxygen infiltration rate, the carbon dioxide production rate is equal to the rate of seeping, and the gas in the package reaches a low oxygen and high carbon dioxide. (relative to air) gas equilibrium concentration. If the equilibrium concentration of the gas in the package causes the fruits and vegetables to produce aerobic respiration that can only maintain the minimum energy required for life activities, at this time, the fruits and vegetables are placed in the optimal atmosphere storage environment, thereby delaying the maturity and achieving the purpose of preservation.