As for the solution of optimal control issues under conditions of complex restrictive conditions, this paper proposes a segmented low-order Gauss pseudospectral method. In this paper, a nonlinear program issue is obtained by the basis of conventional Gauss pseudospectral method and the temporal intervals compartmentalization. During each subinterval, low-order Gauss numerical integration is utilized for discreteness performance of Bolza problem; the property of interpolated type numerical integration is utilized for discreteness of differential state equation; low-order Gauss pseudospectral method is utilized to process complicate constraints. The method overcomes the shortcomings of a higher order of interpolation polynomial and an unstable numerical solution caused by producing Gaussian points at the interval directly under the situation of complex state orbit and control function, thus, having high local algebraic precision and small computation in numerical solution. Ultimately, the method is applied to optimal trajectory planning for air-to-ground operations. The result shows that the algorithm is effective and feasible.