A control method and a cook-chill system of a refrigerator/freezer combination which preserves for a long time the taste of foodstuffs after a cooked foodstuff is refrigerated rapidly and is stored by supplying a lot of chilling air of a freezing chamber into a cook-chill chamber are disclosed. The cook-chill chamber has a three-dimensional storage space for chilling rapidly and preserving cooked foodstuffs, has a first chilled air inlet hole connected with a first chilling air duct which is prolonged from a freezing chamber of which one side of the upper side has a second chilled air inlet hole connected with a second chilling air duct which is prolonged into a refrigerating chamber from a freezing chamber. Also, a cook-chill chilling fan is provided at the first chilled air inlet hole and allows the chilling air in the freezing chamber to flow into the cook-chill chamber, and a cook-chill circulation fan is provided at the second chilled air inlet hole for circulating the chilling air in the cook-chill chamber. A cook-chill operating switch enables a user to turn on/off an operation of the cook-chill system, and a control unit drives the cook-chill chilling fan and the cook-chill circulation fan according to an output signal of the cook-chill operating switch.