Abstract
In a gas pipeline design, compressor station spacing is relative to gas temperature inside of a pipeline when design pressure of a gas pipeline is given. It is feasible to assume that gas temperature is unchanged in hydraulic calculation when gas temperature change along pipeline is relatively small. It is necessary to consider thermal calculation when the temperature change along pipeline is enough large. Combining with BWRS equation of state and hydrodynamic calculation formula, basic calculation formula of temperature drop along pipeline was deduced based on energy conservation law. Calculation steps of calculating length, average gas temperature and temperature distribution along pipeline were presented. As shown by example calculation and analysis, thermal calculation is very important to a gas pipeline design.