In order to investigate aerodynamic characteristics of square cross-section missile, square cross-section missile with fin plane and, and then the aerodynamic characteristics of square and circular cross-section missile through CFD numerical simulation. The result indicates that the square cross-section missile can generate more normal force and lateral force and moment than the circular cross-section missile, and the square cross-section missile with fin plane can generate less lateral force and moment than the square cross-section missile with fin.