Aiming at analyzing the dynamic characteristics for the suborbital launcher, the six-degree dynamics model for the suborbital launcher was established. Taking the designed rocket as an example, the linearization process for the dynamic model was clearly deduced. Subsequently, the linear equation of the pitching motion was obtained. Based on the quantitative analysis of dynamic coefficient, the transfer function was simplified. Finally, the simulation was carried out for the designed suborbital launcher. The results prove that the rocket are working at statically stable state on 1.676 Ma, but statically instability on 5.580 Ma, which is in accordance with the expected target of the experimental aerodynamic data. This paper lays the foundation for the flight control system.