Provided is a wall-mounted fresh air processor. The wall-mounted fresh air processor comprises a fresh air processor box body, a fresh air controller, an air inlet pipe, an air inlet, an air inlet fan, a fresh air purification device, a heat exchanger, a fresh air supply opening, an air return opening, a return air filter, an exhaust fan, an exhaust outlet and an air exhaust pipe. The wall-mounted fresh air processor is characterized in that besides the fresh air supply opening, an adjacent room fresh air supply pipe can be further arranged, the air inlet pipe, the air inlet, the air inlet fan, the fresh air purification device, the heat exchanger, the fresh air supply opening and the adjacent room fresh air supply pipe are connected in sequence to form a fresh air duct, and the air return opening, the return air filter, the heat exchanger, the exhaust fan, the exhaust outlet and the air exhaust pipe are connected in sequence to form a return air duct. According to the wall-mounted fresh air processor, outdoor air is purified to form fresh air, the fresh air is conveyed to one room, the fresh air flows to the other room, and is mixed with polluted air, and finally the mixed air is exhausted through the wall-mounted fresh air processor; due to the fact that the same wall-mounted fresh air processor is shared by the two rooms, the wall-mounted fresh air processor is made full use of, and the user cost is reduced.