The maneuverable trajectory optimization issues were addressed from the point of view of optimal control with multi-constraints. First, dimensionless dynamic equations of maneuverable trajectory were formulated and critical parameters were found. Second, the Legendre pseudo-spectral method was adopted for transferring the optimal control problem into non-linear programming formulation solved by the SQP method. A numerical example was tested to explain the method's rationality and effectiveness. In addition, relations between critical parameters and maximum range were resolved, and results illustrate that the maximum lift-to-drag ratio is vital for maximum range and the reference lift-to-weight ratio has some influence on maximum range.