In this paper, a characteristic model based longitudinal control design for the trans-aerosphere vehicle X-34 in its transonic and hypersonic climbing phase is proposed. The design is based on the dynamic characteristics of the vehicle and the curves it is to track in this climbing phase. Through a detailed analysis of the aerodynamics and vehicle dynamics during this climbing phase, an explicit description of the tracking curve for the flight path angle is derived. On the basis of this tracking curve, the tracking curves for the two short-period variables, the angle of attack and the pitch rate, are designed. An all-coefficient adaptive controller is then designed, based on the characteristic modeling, to cause these two short-period variables to follow their respective tracking curves. The proposed design does not require multiple working points, making the design procedure simple. Numerical simulation is performed to validate the performance of the controller. The simulation results indicate that the resulting control law ensures that the vehicle climbs up successfully under the restrictions on the pitch angle and overloading. In this paper, a characteristic model based longitudinal control design for the trans-aerosphere vehicle X-34 in its transonic and hypersonic climbing phase is. The design is based on the dynamic characteristics of the vehicle and the curves it is to track in this climbing phase. Through a detailed analysis of the aerodynamics and vehicle dynamics during this climbing phase, an explicit description of the tracking curve for the flight path angle is derived. On the basis of this tracking curve, the tracking curves for the two short-period variables, the angle of attack and the pitch rate, are designed. An all-coefficient adaptive controller is then designed, based on the characteristic modeling, to cause these two short-period variables to follow their respective tracking curves. The proposed design does not require multiple working points, making the design procedure simple. Numerical simulation is performed to validate the performance of the controller. The simulation results that that resulting control law ensures that the vehicle climbs up successfully under the restrictions on the pitch angle and overloading.