During the operation of oil immersed paper bushings for reactors in Xinjiang, due to the influence of extreme external temperatures and oil temperatures, the thermal stress inside the bushing frequently changes, making it highly susceptible to discharge breakdown faults. Therefore, it is necessary to consider replacing the bushings with oil-free and explosion-proof epoxy impregnated paper bushing for operation. In order to accurately evaluate the thermal and electrical properties of adhesive impregnated paper bushings under extreme environmental temperature and oil temperature changes, This article establishes a multi-physics coupling model of electric-thermal-flow for epoxy resin impregnated paper bushings of 750kV high voltage reactors, and analyzes the thermal field distribution inside the bushing and radial electric field distribution of capacitor core when the ambient temperature (−40 ℃ ~ 90 ℃) and the oil temperature (−10 ℃ ~ 90 ℃) changing. The results shows that the temperature of the bushing increases with the increasing of ambient temperature, and the hottest point temperature position of the conductive rod showed an upward trend with the increasing of ambient temperature. The distribution of electric field is less affected by environmental temperature.