Abstract: Bohai A oilfield belongs to heavy oil field. The efficient development of this oilfield can provide experience for largescale thermal recovery and development of Bohai oil field. Heat utilization efficiency is a key index to evaluate the effectiveness of thermal recovery development, and the heat insulation measures have a great impact on heat utilization efficiency. In order to reduce heat loss, it is necessary to carry out corresponding research and propose insulation measures in a targeted manner. Based on the actual wellbore structure designed by ODP in this oilfield, this paper makes a preliminary optimization of the heat insulation mode, and analyzes the factors affecting steam dryness. At the same time, it also demonstrates the influence of adding heat insulation tools on steam dryness. It shows that the combination of the heat insulation casing + heat insulation tubing + annular nitrogen injection + heat insulation coupling + heat insulation tool group, the heat loss of the wellbore is minimum, and the steam dryness of the bottom hole is the largest. The efficient insulation measure has guiding significance for the subsequent injection heat process of thermal recovery wells in A oilfield.