Abstract: An optimization model was presented for selecting the optimal from various projects. At first, six evaluation indexes of three types of scales were compared with each other, which were concluded en/5 exponential scale. Also by integrating both the theory of relative relation grade and AHP, a mathematic model was established to optimize biomass energy development projects and was practically tested in the case of optimizing biomass energy development projects of Zhejiang Province. The result showed the synthesizing value of biomass biogas project was 0.8884, namely, indicating it was the best project. The optimization model and decision-making system established in this paper are arguably characterized by advantages of wide application, easy maneuverability, and they have a practical denotation.