The utility model relates to an automatic thawing device of a natural ventilation cooling tower; a circulating above-water tower pipeline is connected with a pipeline pump which is connected with a thawing mother pipe which is laid along the cooling tower; the thawing mother pipe is provided with at least one stand pipe, and the front end of each stand pipe is provided with a thawing pipe which is installed along the upper edge of an air inlet of the cooling tower and is provided with a spray head; a water inlet electric valve is arranged between the circulating above-water tower pipeline and the pipeline pump; each stand pipe is provided with a thawing pipe electric valve; the water inlet electric valve, the pipeline pump and the thawing pipe electric valve are connected with a PLC controller; and an input end of the PLC controller is connected with an electronic thermometer. The automatic thawing device of the natural ventilation cooling tower has the advantages that 1, the device can prevent the cooling tower at the cold area from being frozen under the conditions of less investment and operation cost, thus ensuring a machine set to safely run; and 2, the running and stopping of the thawing device can be controlled in a full-automatic way, so that the automation level of a power plant can be improved.