The invention discloses a heat conduction oil replacement method of an intelligent constant temperature device of an electrical cabinet. The method comprises an electrical cabinet body, a refrigeration and heating device, an internal heat exchanger, an external heat exchanger, a first drive oil pump, a second drive oil pump and multiple temperature sensors, wherein the refrigeration and heating device, the internal heat exchanger, the first drive oil pump, the second drive oil pump and the plurality of temperature sensors are arranged in the electrical cabinet body; the external heat exchanger is arranged at the outer side of the electrical cabinet body; and the refrigeration and heating device comprises a heater, a refrigerator, a controller, multiple groups of semiconductor refrigeration pieces and a shell. By the heat conduction oil replacement method of the intelligent constant temperature device of the electrical cabinet disclosed by the invention, an oil medium function can be automatically replaced; a new oil medium achieves full filling work of the oil medium in each segment of pipeline through full drive of each segment of oil pipeline; a blank pipeline phenomenon caused by pipeline oil replacement leakage is avoided; and meanwhile, the heat conduction efficiency and safety of an oil-way are also ensured.