In a large braking environment, the head of the pilot would collide with the head up display (HUD) because of the aircraft pilot's body leaning forward under inertia. And the preload of the HUD determines whether the head is injured during the collision. Therefore, it is necessary to design a test component for investigating the influence of the mounting preload on head injury during the collision. Consideration of pilot safety, in this paper, the motion characteristics of the pilot is analyzed, and a component of head injury criteria tester for head impact test is established. Given the short-time and high-speed characteristics of the head impact, the driving method adopted hydraulic ejection. This method effectively solves the problems of space limitation and non-reusability in traditional methods. The computational fluid dynamics model and kinematic model of human body are used in this study to simulate the acceleration process. The AMESIM simulation model is set up to study the influence of key parameters on the velocity, angle and acceleration of the system collision moment, to optimize the system parameters and to be verified through experimental studies. The ultimate objective is to achieve that the linear velocity is 11 m/s when the test component rotates at a specified angle. This research can be referred to in the design of a component HIC tester and the study on optimization of fluid flow dynamic characteristics.INDEX TERMS Preload of the HUD, head injury criteria tester, head impact test, hydraulic ejection, optimize parameters.