The invention provides a refrigeration system and a control method thereof. The refrigeration system comprises a compressor, a condenser, an electronic expansion valve, an evaporator, a cooling mediumpipeline, and a temperature controller, the cooling medium pipeline is provided with a cooled medium, and the cooling medium pipeline penetrates into the evaporator to enable a refrigerant and the cooled medium to conduct heat transfer in the evaporator; and the temperature controller is arranged on the cooling medium pipeline, and the temperature controller is arranged on the air outlet side ofa condensing fan, so that heat transfer is carried out between hot air blown by the condensing fan and the cooled medium in the cooling medium pipeline passing through the temperature controller. According to the refrigeration system and the control method thereof, the cooled medium in the cooling medium pipeline can be heated by the hot air blown by the condensing fan in the temperature controller, condensation waste heat is fully utilized to heat a cooling medium to the target temperature range, stability of the refrigeration system is improved, electrical heating with poor safety is avoided, and system performance, reliability and security are improved while the design difficulty is lowered.