Abstract: By analyzing and comparing nature gas pipeline calculation formula in common use, the adjustment and reconstruction project of the active duty of nature gas pipeline system was studied in the paper, considering the fact running status of the nature gas pipeline, the calculation formula applying the active duty of nature gas pipeline was presented. According to the mathematical model established, the waterpower calculation of the gas pipeline was done, and the gas pipeline system that needs to adjust and reconstruct or not was put forward. When the gas pipeline system need to adjust, three projects was presented in this paper: the first one is to add the compressor station to the old nature gas pipeline network, the second is to replace part of segment in the existent gas pipeline, and the last is to lay the looped pipeline. The three projects were successful to be applied in the gas pipeline at Southwest Area in Sichuan.

Key words: nature gas pipeline, adjustment and reconstruction, compressor station, looped pipeline, changed diameter pipeline