The current transformer converts the large current in the primary system into a small current for secondary measurement and measurement protection in the power system. It has an indispensable effect on the stable operation and fault current measurement of the power system. During the online operation, the abnormal increase in gas of the oil inside the transformer caused by partial discharge, heat failure, etc., caused the internal pressure to increase sharply, which easily caused insulation damage and explosion. In order to study the internal temperature field distribution of the transformer and the influence factors of pressure changes, and to find the internal pressure surge failure in time, this paper uses ANSYS Fluent software simulation to establish a 220kV inverted oil immersed current transformer model, using finite element analysis and multiphysics coupling analysis The internal temperature field distribution law of the inverted oil immersed current transformer was obtained by other methods, and an experimental platform for the inverted oil immersed current transformer was established to verify the validity of the simulation. Meanwhile, the pressure online based on the MD-TPR transformer was designed. The monitoring device obtained the characteristics of the internal pressure influence of the transformer.