Abstract: A long distance steam pipeline is considered as a whole. The pressure loss of the pipeline is calculated by friction theory and the temperature drop is calculated by heat dissipation from insulation layer and a method of equal enthalpy pressure drop. As a result，the calculated value is smaller than the measured value. To solve the problem，a temperature-pressure coupling segmentation calculation strategy is proposed. The pressure loss calculation method still uses friction theory，while the temperature drop calculation method takes into account three factors: heat dissipation from insulation layer，equal enthalpy pressure drop and heat dissipation from supports. The way of decoupling is to calculate the pressure loss first，and then the temperature drop is calculated. After these improvements，the calculated pressure loss and temperature drop basically match with the measured values，which satisfies the required accuracy of the project.

Key words: Steam production from waste heat recovery, Long-distance steam pipeline, Pressure loss, Temperature drop, Temperature-pressure coupling