Abstract: During the process of injected hot fluids by thermal recovery in heavy oil wells,heat insulation technology is generally adopted by reducing heat conduction and heat convection,while the control of the thermal radiation is less considered,therefore,a new insulating technology combing heat insulation coating and vacuum techniques is provided.The technology can minimize thermal conductivity within casing-tubing annulus and reduce emission coefficient of the tubing outer wall to achieve the effect of lowering the thermal radiation.Compared with the traditional wellbore insulation technology,through the calculation of the WELLFLOW software,the heat insulation technology is of 67%-80%less wellbore heat loss.The technology has great potential for promoting thermal recovery of offshore oil fields for its simple process and convenient advantage of equipment installation.