With the anticipation of strict environmental directives, green design has become a critical and inevitable issue for manufacturers. Principles of product green design are not only the hot topic but also become highest standards for business. Even more is the main stream of development sustainable products. Some of development country already set up standards of products design and produce. Green design is a new type of design, and it is the effective integration of design methods and tools. In order to estimate the influences caused by a green design project, the Fuzzy decision model is proposed to help determine the best alternative. The proposed model could calculate the effect in aspects of quality, environment and cost. It is expected that this model can not only fully evaluate the effect of a green design project, but also help determine the best strategy for green product design. A case is also proposed to reveal the applicability of this model.