Abstract: Stream injection is the main production technology for heavy oil. In order to decrease heat loss of stream, insulating treatment to stream pipeline is necessary, however, there are some problems like unfitted insulation material, unreasonable insulation structure in the work. Based on insulating effectiveness test, selection and optimization in site, the insulation structure with double-layer of composite silicate plus reinforced high-temperature resistant plastic case is determined, and its thickness of insulating layer is 100 mm. Insulating over valve, pipe clamp and pipe bracket are made. By means of the insulation, heat loss of steam pipeline lowers down to 150 W/m², loss rate/km of pipeline is controlled within 3%, and the total heat loss is kept at the national standard. Finally, stream loss is decreased for heavy oil production with those insulation treatments.