In this paper, the performance of trajectory optimization-based mid-course guidance of long-range missiles is analyzed. Trajectory optimization has the advantage of being able to apply the nonlinear dynamics of the missile and various constraint conditions, optimization must be repeatedly performed to compensate for model uncertainty and disturbance. Since the optimization requires a large calculation time, it cannot generate a command in a short period. Therefore, the performance of the mid-course guidance is analyzed according to the optimization period. In addition, since the flight time is long, the actual intercept point may be very different from the initially expected intercept point when the target maneuvers. Considering this fact, the performance of the guidance technique is compared according to the definition of the expected intercept point. Finally, we analyze the performance of trajectory optimization-based guidance and PN (Proportional Navigation) guidance.