Abstract: For grassland dwellings in western Inner Mongolia,it has single enclosure structure,backward heating method,low heating efficiency,poor indoor thermal environment quality and large waste of petrochemical energy causing environmental pollution.Aiming at ultra-low energy consumption, this paper makes full use of abundant local solar and wind energy resources to construct a new heating system composed of wind power generation system,passive solar room and insulated curtain system and solar hot water circulation system to solve these problems.Based on the new system,the orthogonal experiment is used to study the seven main factors affecting the envelope structure,including the depth of the solar room,the material of the window frame,the ratio of the south-facing window to the wall,the material of the glass,the thickness of the insulation layer,the material of the insulation layer,and the material of the wall.By analyzing the energy consumption indicators,the best combination plan is selected.The results show that:compared with the original scheme,the annual energy consumption of the optimized combination scheme is reduced by 12674.79 kw·h,and the energy consumption reduction rate is 77.99%.The average indoor temperature increased by 8.77℃ and PMV increased by 1.86,which meets the requirements of indoor heating and comfort in winter.