Abstract: Many underground pipelines are carried with heating tracer in permafrost region. To evaluate the thermal conditions of underground pipeline with heating tracer, the first thing to do is to understand unstable temperature field around the pipeline. This article analyzes the geometrical properties of the pipeline with heating tracer, sets up the mathematics model and calculates the two-dimensional, unstable temperature field and heat flux density field of soil around the pipeline by using finite elements method. The temperature field and heat flux density field are calculated when no insulation board is set on the pipeline and heating tracer. The temperature field and heat flux density fieldof soil are obtained when the width and thickness of the insulation board are modified, and the results are analyzed.