In order to more accurately and efficiently determine the loss and heating state of the magnetic pole area of a tubular hydro-generator, this study establishes a comprehensive 3D electromagnetic field-thermal network analysis model of its pole area and implements calculations according to its rated symmetrical operating conditions. A 36 MW large tubular hydro-generator is used as an example. Based on the measured results of the pole temperature and the use of the calculation hardware, the results are compared with the traditional electric circuit-magnetic circuit-thermal circuit method and 3D electromagnetic field-temperature field finite-element method. It is shown that the 3D electromagnetic field-thermal network model established in this study has several advantages, including high calculation accuracy, short calculation time, and low hardware consumption. These results have important value in improving the electromagnetic-temperature analysis and design of poles in large hydro-generators.