A scientific and practical decision-making model for the optimization selection of green building renders as an important guarantee for the success of green building. Considering the effective use of resources, building indoor environmental quality and environmental load of green building, an appraisal index system of green building was established. Several green buildings were evaluated based on the relative membership degrees that obtained from a fuzzy extension model which integrated the idea of fuzzy mathematics, extension theory and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The feasibility and practicability of the model is verified by the example.