With the continuous development of China’s construction industry and the continuous adjustment of energy structure，the photovoltaic curtain wall using new energy has achieved initial results in energy conservation and emission reduction，but when the photovoltaic system works，there is still a rise in the temperature of the back plate of the photovoltaic panel and affect its work efficiency，which in turn leads to the problem of increased energy consumption． Therefore，it proposes a new type of energy-saving and environmentally friendly air-cavity structure photovoltaic curtain wall，on the one hand，to study the influence of the external surface of the wall and the air cavity between the photovoltaic backsheet on the heat dissipation efficiency．On the other hand，the principle of Seebeck effect is used to study the relationship between heat absorption and the efficiency of photovoltaic panels by the copper－constantan thermocouple thermoelectric conversion device on the back of photovoltaic panels．Finally，through the analysis of the experimental data，it is concluded that the heat dissipation efficiency of the photovoltaic building wall based on the Seebeck effect increases with the increase of the width of the air cavity，and the utilization of the heat of the photovoltaic backsheet by thermocouples can promote the improvement of the efficiency of the photovoltaic panel．