Disclosed are a fixing structure of insulation panels and a prefabricated refrigerator with the same. The fixing structure of insulation panels includes a recess recessed on one surface of a first insulation panel having an insulation portion inside a casing, and a protrusion formed to be inserted into the recess, on one surface of a second insulation panel having an insulation portion inside a casing, wherein the insulation portions of nonmetal material are exposed to a bottom of the recess and a front end of the protrusion so as to shield a transmission path of heat flowed along a casing contact surface of the insulation panels, thereby improving insulation efficiency.