The utility model aims to disclose a large-diameter double-connecting-pipe-seat integral forging type main pipeline hot section structure. The main pipeline heat section structure comprises a main pipeline heat section body, a fluctuation pipe connecting pipe base and an ADS (automatic pressure relief system) connecting pipe base, the fluctuation pipe connecting pipe base and the ADS connecting pipe base are integrally forged and integrally forged with the main pipeline heat section body, and the fluctuation pipe connecting pipe base and the ADS connecting pipe base are arranged on a long straight section of the main pipeline heat section body respectively; Compared with the prior art, the method has the advantages that the cost is low;, Pipe connecting seat through fluctuation pipe, the ADS connecting pipe seat and the main pipeline hot section body are integrally forged; Reducing weld count, Reducing welding period, the in-service inspection workload of a high-level amplification area is greatly reduced; the thermal stratification stress of the fluctuation pipe is reduced; the steam discharge function requirement of the ADS adapter under an accident is met; The requirements for the hole forming position of the ASME NB-3683.8 connecting pipe base are met, the steel ingot consumption of the forged connecting pipe base is reduced, the forging heating number is reduced, the machining amount of a main pipeline manufacturing machine is reduced, the grain size of a pipe nozzle is improved, the manufacturing difficulty is reduced, the manufacturing cost is reduced, and the purpose of the utility model is achieved.