Disclosed is a freshness preservation unit for a storage box of a refrigerator. At least one through hole is provided on at least one box wall of the storage box. The freshness preservation unit comprises a housing wherein an accommodating space is formed. A freshness preservation film is provided in the accommodating space. The housing is provided with a fixing piece which is cooperatable with the box wall of the storage box such that the freshness preservation unit is assembled in the through hole of the storage box in a detachable manner. The freshness preservation unit realizes the functions of freshness preservation and storage for fruits and vegetables, and is assembled in the through hole of the storage box in a detachable manner, convenient to assembly and disassembly, convenient to cleaning and replacement, and low in the maintenance cost.