This paper describes a midcourse trajectory optimization for long-range missiles with a seeker field-of-view limit. Trajectory optimization is performed using convex programming, which is effective for real-time applications. Field-of-view limit, minimum dynamic pressure, and angle-of-attack limit are considered as path constraints. The terminal velocity is used as a performance index to ensure maneuverability in the terminal homing phase. The discontinuity of dynamics at the end of boost time is solved by separating the flight phase into a boost phase and a glide phase. The nonlinear dynamics are converted to input affine form using new input variables and partially linearized. The admissible input set is relaxed into a convex set through lossless convexification. Slack variables are introduced in the quadratic trust region and linearized path constraint, where they are augmented into the performance index for robust convergence. The transformed dynamics are discretized through a pseudo-spectral method and optimal trajectory is obtained using sequential convex programming. The effectiveness and robustness of the proposed method are verified through numerical simulation.