The qualitative differential game theory is used to study the pursuit-evasion game of Unmanned Aerial Vehicle (UAV) and Unmanned Ground Vehicle (UGV). The process of determining the dividing barrier between the escape area and the capture area in the presence of obstacles in the environment is studied. The scene of the game is set, and the kinematic equations on both sides of the game are established. The outcome of the game is analyzed according to the kinetic characteristics of both sides in order to obtain the game strategy. Then the impact of the obstacles in such environment and the conditions of game termination are analyzed. Finally the barrier is obtained, and an example illustration is given.