There is an important significance for the design and the life time evaluation of the dry-type transformer based on the hot-spot temperature.At present the methods of obtaining the transformer’s hot-spot temperature are as follows:direct measurement and numerical calculation.Direct measurement can obtain winding hot spot temperature through the firber optic temperature sensor or thermocouple;The numerical calculation mostly uses the finite element or finite difference method.This paper establishes the inversed-heat transfer caculation model of high and low voltage windings.Using the high-precision infrared sensor to acquire the temperature of the high voltage widing.Through calculation the temperature distribution of the low voltage winding has been obtained and the hottest spot temperature of the widings is very closed to the result obtained by the IEEE model in a certain range.It provides a new method for the acquisition of the hottest spot temperature of the dry-type transformer.