This paper presents an optimization technology for the molecular design of environmentally friendly solvents for extractive distillation. The approach based on the concept of group contribution methods (GCM). To decrease the complexity and random of design problem, a set of functional groups are pre-selected based on the modified UNIFAC method. Combination of groups can produce different molecule, once the molecule is generated, the properties are evaluated to determine if it satisfy the criteria. The criteria include separation performance and environmental performance. Simulated annealing algorithm is used to search feasible molecular structures. The molecule transition strategies and parameters of algorithm are described detailedly. Finally, the method is demonstrated with two examples, and the design results show that the proposed technology is a valid technology to design the desirable solvents.