Aimed at the complicated structure and remarkable rigidity of its process, a method of hierarchical division optimization of flight line maintenance value stream based on GA and DSM is proposed. The value flow transferring model is built on the actual condition. According to its character of time-delay and propagation, an decoupling clustering method to improve the effect of value flow transferring is deduced. Then, its particular steps are given. The projection relationship between DSM model and cluster of value activities is defined. Futhermore, fitness function based on cluster weight, cluster scale, cluster number and decoupling parameter are designed. Therefore, The algorithm of value activities cluster based on GA and clustered activities decoupling decoupling. Finally, combining with case study of a military airfield. the validity of the model is proved, and the optimization pattern of flight line maintenance value stream is established.