To analyze the heat source of the bearing-support system, the heat source mainly includes the heat transfer between the main flow path and the support structure, the heat generated by the high-speed roller bearing, the heat generated by the seals inside the bearing-support system, the heat transfer between the high-temperature environment outside the bearing chamber and the wall surface of the support structure, the heat transfer of the shaft, as well as the heat generated by the gears and splines. 1D thermal-fluid coupling calculations of the bearing-support system are carried out to obtain the wall temperature and convective heat transfer coefficient (HTC) of the compressor/turbine intermediate bearing support frame, respectively. The wall temperature of the right frame of the compressor intermediate support system increases radially upward by 1.73%, and HTC increases radially upward by 20 times due to the presence of interstage sealing between the main flow path and the disk cavity. The intermediate bearing support frames of the aero-engine compressor and turbine are analyzed for heat generation separately to evaluate the effects of different heat sources on the heat generation of the bearing-support system under cruise operating conditions. Among them, the heat sources with the highest percentage of heat generation are through the support walls, bearings, and seals, and heat generation by the seals in the bearing-support system accounts for 29% in the intermediate bearing support frame of the compressor and 35% in the intermediate bearing support frame of the turbine. Therefore, by optimizing the number and location of seals in the bearing-support system, the heat generation in the bearing-support system can be significantly reduced, and the bearing chamber oil feeding rate can be further reduced.