In recent years, the construction and operation of buildings have accounted for as much as 32 percent of Chinese total social energy consumption, and transforming the construction method and deepening the operation of energy conservation have become the focus of energy conservation in the construction industry. In order to study the cooling and carbon reduction effect of low-carbon photovoltaic modular rooms, three test rooms were built in Tianhe District of Guangzhou City to conduct comparative measurements of cooling and carbon reduction, and to compare and analyse the internal surface temperature of the roof, the internal surface temperature of the external wall, the indoor air temperature and the air conditioning power consumption of low-carbon modular BAPV (building attached photovoltaic) and BIPV( building integration photovoltaic) rooms with that of the ordinary rooms. The test results show that for Guangzhou area, under natural ventilation conditions, low-carbon modular BAPV and BIPV rooms can significantly reduce the internal surface temperature and air temperature of the room compared with ordinary rooms, improving the indoor thermal comfort environment; under air-conditioning conditions, low-carbon modular BAPV and BIPV rooms can effectively reduce the power consumption of air-conditioning compared with ordinary rooms, with an energy-saving and carbon-reducing rate of up to 18.7%, which is a remarkable effect of carbon-reducing.