In mission planning of UCAV formation, the flight route optimization is an important research topic. The optimum flight route of UCAV based on uncertain linguistic preference information is studied. First, the indicators for evaluating the UCAV route are presented, and the definition of uncertain linguistic decision matrix is described. Then, analysis is made to the expected possibility and mathematical expectation of each index corresponding to the flight route, and the group decision-making optimum flight route analysis method based on uncertain linguistic preference information is given. Finally, a numerical example is given to illustrate the usage of the proposed approach.