A portable refrigerator includes a main housing, a refrigerator cover, a cooling mechanism, a rechargeable battery pack and a control unit. The cooling mechanism includes heat exchanging tubes, a compressor, an evaporator and a condenser connected to the evaporator and the compressor. The rechargeable battery pack is detachably attached on a power compartment of the main housing. The control unit is supported in the main housing and electrically connected to the rechargeable battery pack and the cooling mechanism for centrally controlling an operation of the cooling mechanism. A predetermined amount of refrigerant is arranged to controllably pass through the heat exchanging tubes, the condenser, the evaporator and the compressor for extracting heat from the accommodating cavity.