Freshness preservation unit, storage box, and refrigerator

A freshness preservation unit for use in a storage box of a refrigerator, wherein the freshness preservation unit comprises a housing, an accommodating space is formed in the housing, a freshness preservation film is provided in the accommodating space, the housing is provided with a fixing piece, and the fixing piece is configured to be cooperatable with the box wall of the storage box such that the freshness preservation unit is assembled in a through hole of the storage box in a detachable manner, wherein

• the storage box is a cubic structure including six box walls,
• at least one box wall of the storage box is provided with a plurality of the through holes,
• a shape of the freshness preservation unit matches the through hole, and
• a plurality of the freshness preservation units can be selectively filled into different through holes as required according to corresponding position of an evaporator or an air inlet in a refrigerator and according to a corresponding relative position of the storage box, so that a general-purpose storage box with a variable position in a refrigerator is thereby obtained.