PurposeThe purpose of this paper is to study a finite‐thrust orbital transfer optimization problem via a new optimal control method‐Gauss pseudospectral method.Design/methodology/approachBased on the dynamic equations with the pseudo‐equinoctial elements as state variable, optimality condition is derived and the optimization problem is converted into nonlinear programming problem. Gauss pseudospectral method is used to avoid the two‐point boundary value problem. The dynamic equations are converted into static parameter optimization problem. The state variables and control variables are selected as optimal parameters at all collocation nodes. Two numerical examples of orbital transfer with coplanar and different planes are analyzed, respectively.FindingsThe simulation results demonstrate that Gauss pseudospectral method is not sensitive to the initial conditions of orbital transfer. They also show good robustness and control facility.Originality/valueThe precision and efficiency of this trajectory optimization method are demonstrated by applying it to space vehicle orbital transfer with finite thrust optimization problem.