Based on the evaluation analysis of the energy characteristics of products, an energy optimization performance assessment model was presented taking into account economical effectiveness, environmental performance and uncertainty of energy consumption factors of use phase. In accordance with using process of energy optimization, the economy analysis model and environment analysis model were established. Uncertainty factors influencing energy optimization were analyzed and modeled during the usage stage. Therefore the evaluation value of energy optimization performance was obtained. Then the product design scheme was evaluated by applying fuzzy information axiom method, and the optimal design scheme was acquired. At last, a product case was given to verify the assessment method.