Abstract: The influence of temperature field and moisture field variations of buried pipeline on pipeline construction is studied and authors consider that numerical simulation calculation is an effective means to predict temperature field of buried pipelines. Taking the permafrost distributed over China as a background, transport issues in non-saturated soil water and thermal coupling are researched. Soil's freezing behaviors of freezing process is discussed and a mathematical model for coupling transfer of water and heat in soil is established, and the process of soil freezing with finite deference method based on numerical simulation technique is calculated.