Abstract: With the continuous improvement of people's requirements for room comfort, fresh air system has gradually become an indispensable and important part of air conditioning system, however, the energy consumption caused by fresh air system cannot be ignored. To reduce the energy consumption of fresh air system and improve the energy utilization rate, a modular energy-saving wall with two-stage fresh air treatment based on solar energy was designed in this paper. The design was based on solar thin-film photovoltaic power generation technology, and the battery was added to ensure its operation durability. At the same time, the common fresh air equipment adopting exhaust heat exchange was improved, and the thermoelectric refrigeration heat pump system was added to realize two-stage treatment of fresh air. The applicable air volume range of the device was 60-90 m³/h, fresh air cooling was used in summer, the supply air temperature was between 28 ℃ and 31 ℃, and the sensible heat exchange efficiency could reach 86.7%. In winter, the temperature of fresh air rose, the supply air temperature was between 12 ℃ and 20 ℃, and the sensible heat exchange efficiency could reach 79.0%. Compared with the primary air supply, the sensible heat exchange efficiency of the unit increased by 26%-28%, which realizes the deep heat recovery of fresh air, reduces the energy consumption of air conditioning equipment, and achieves the energy-saving effect of residential air conditioning and heating.