The trajectory characteristics of the near-space hypersonic glide vehicle are mainly under the influence of the initial state of glide segment and control law of the vehicle. Therefore, the influence of glide segment initial state on trajectory characteristics of hypersonic glide vehicle was studied under the condition that the control law of vehicle is determined. According to the different forms of glide trajectory, under the condition of longitudinal equilibrium glide, the analytical formula of the vehicle state variable was derived theoretically, and the uniqueness of initial state of the equilibrium glide trajectory was analyzed in combination with the equilibrium glide condition. Under the condition of longitudinal skip glide, the evaluation indices of trajectory performance were constructed, and the initial state of glide segment with optimal trajectory performance was found by using the group intelligence algorithm. Through the single factor sensitivity analysis, the sensitivity analysis of the initial states of two forms of glide trajectory was carried out, and the initial velocity of initial state has the greatest influence on the trajectory characteristics. The analysis of the uniqueness and optimality of initial state can be used for reference in the trajectory design, trajectory tracking, trajectory prediction and trajectory optimization of hypersonic glide vehicle.