The global climate change directly affects the weather pattern of Taiwan. Some research achievements show that buildings will decrease the indoor room temperatures by 1oC during summer and increase the indoor room temperature by 1oC during winter with 6%~10% savings of energy consumption. In this research, the phenolic resin board is used as an experimental roof insulation material in a green roof that is covered with living plants for the objective of reducing summer building air conditioning energy consumption and cost. The influence of roofing materials with various insulation capacities on the building interior temperature is simulated in this study using the basic thermal data measured in the laboratory. Analysis results of computational fluid dynamics, CFD simulation of the temperatures are close to the measured data. Simulation of the insulation capacity of the green roof indicates that the difference between outside and inside temperature is as high as 29°C that demonstrates the insulation capacity of the phenolic resin board. In addition to save energy, the combined insulation technology using phenolic resin board and planted green vegetation coverage on the roof will also contribute to a green and aesthetic environment.