A method for calculating the carbon energy of an urban residential building system is provided. The method comprises: according to the distance from a heat exchange station, dividing the region into aplurality of types of regions, randomly selecting at least five measured points in each type of region, and finally determining the area, the orientation and the layout of a building unit of each measured point, and a positional relationship with the surrounding public space to obtain a heat transfer coefficient of the outer wall, the roof and the outer window; and using a data perception systemfor perception to obtain the indoor temperature, the indoor humidity, the indoor CO2 concentration, and the real-time power consumption of the household, and through model calculation, forming data ofenergy consumption and carbon emissions, and storing the data into a cloud server. According to the method provided by the present invention, the limitation of the previous carbon energy measurementfield only to the building monomers is broken through, and a set of system capable of monitoring and evaluating the carbon energy condition of the building system is formed; and the problems of the energy consumption and carbon emissions of domestic hot water is considered in the evaluation system, so that the result can be more scientific.