Abstract: The Line C of the China–Central Asia Gas Pipeline is a typical gas pipeline characterized by high transmission pressure, large flow, long pipeline span, numerous gas stations and complicated transportation technology. In order to study the changing law of hydrothermal parameters of the pipeline under normal and accident conditions and the self-rescue time of the pipeline under various accidents, a simulation model of the Line C of the China–Central Asia Gas Pipeline was established using SPS software to simulate the pressure and temperature parameters of the whole pipeline under normal conditions. The maximum relative errors of the pressure and temperature, between simulated results and actual operation data are 1.90% and 6.92% respectively, which verifies the reliability of the model. Based on this, the changes in the ambient temperature and the roughness of the pipeline on the gas transmission efficiency over the whole pipeline were analyzed, and the longest self-rescue time of the pipeline under various accident conditions was determined, which can provide a reference for the operation and management of the China–Central Asia long-distance gas pipeline.