The vibration absorption system of the infrared sight is very important for the infrared sight to bear high impact. The vibration absorption effect directly affects the shooting accuracy and reliability of the weapon. Based on response surface method, the parametric modeling and finite element analysis of the infrared sight and its vibration absorption were carried out in ANSYS Workbench. The response surface curve of the maximum displacement response of the vibration absorption system to the structural parameters was simulated under the impact load of 200 g, and then the sensitivity of the structural parameters of the vibration absorption connection device to the maximum displacement response was set: the change rate of the maximum displacement response to the structural parameters, which judged the sensitivity of the maximum displacement response to the structural parameters and guided the direction of optimization. The influence of structural parameters such as width, height and thickness of leaf spring on the maximum displacement response was optimized. The results showed that the width of leaf spring group was the most sensitive parameter. The results of optimization analysis could be directly used to guide the structural design of the vibration absorption system of infrared sight.