The present invention discloses a multifunctional constant temperature refrigerator comprising a compressor (1), an evaporator (16), a condenser (23), a cabinet (37), and freezing compartments (9), wherein the refrigerator further includes a closed cold air flow duct (15) and a negative thermal carrier assembly. The freezing compartments (9) are disposed in the cabinet (37). The closed cold air flow duct (15) is located at a back portion of the cabinet (37). The evaporator (16) is placed in the closed cold air flow duct (15). The negative thermal carrier assembly comprises a negative thermal carrier case (10) filled with negative thermal carriers and a heat pipe (12). The negative thermal carrier case (10) is disposed in each of the freezing compartments (9). A vaporization zone of the heat pipe (12) is extended into the negative thermal carrier case (10), and a condensation zone of the heat pipe (12) is extended into the closed cold air flow duct (15).