We have developed a new evaluation method of “thermal radiative power” (TRP) for investigating the impact of building surface material albedo on urban environment. The simulation system ENVI-met is used. This system is a 3D computer model which analyzes micro-scale thermal interactions within urban environments. It simulates urban-scale environmental conditions such as roofs, exterior wall, and ground surface temperatures. Focuses of this research are on the climate change in urban and community scale in cold climates. The urban environmental analysis is carried out in a typical residential area in the central city of Montreal. The model for simulation is based on the existing urban conditions (building layout, building volume and ground surface properties). The TRP with varied building roof materials is calculated and compared. The effect of building surface materials on local climate is analyzed. The selected simulation area in this research is 300 m by 300 m. Each urban surface (ground, walls, and roofs) is analyzed individually, in order to determine the urban environmental contribution. The interaction between reflective surfaces is discussed. Representing the environmental conditions by TRP could help to define the impact of urban surfaces on the macro-climate (urban level) and micro-climate (community level).