By simulating the temperature changes in pipelines under different transportation conditions, it is found that gases and supercritical media release heat to the environment due to their initial temperature being higher than the ambient temperature. As the pipeline distance increases, the final temperature will be consistent with the pipeline temperature, and the temperature change value is positive; The temperature of the medium in the liquid pipeline at the starting point is much lower than the pipeline temperature, so it will continuously absorb heat from the external environment until the temperature is consistent with the pipeline. Therefore, the temperature change is opposite to the first two and is negative.