Abstract: Closing bounce is one of the core assessment indicators for the mechanical characteristics of high-voltage circuit breakers. Its existence will significantly accelerate the electrical wear process inside the arc-extinguishing chamber, shorten the overall electrical life of the arc-extinguishing chamber, and also cause a series of potential safety hazards such as arc re-ignition, contact welding, and operating overvoltage, which directly threaten the stable operation of the power system. To accurately identify the key influencing factors of closing bounce and provide the optimal parameter combination, this paper adopts the orthogonal design method, selects three engineering adjustable parameters including final contact pressure, closing speed, and moving contact mass as research factors, sets three typical levels for each factor, constructs an L9 (3?) orthogonal test scheme, and carries out systematic experimental research with closing bounce time as the evaluation index. Through range analysis and variance analysis, the influence degree and action law of each factor on closing bounce are clarified, and the theoretical optimal combination is verified by experiments. The results show that the final contact pressure has an extremely significant impact on the closing bounce response, the closing speed has a significant impact, and the moving contact mass has a relatively small impact; the closing bounce time under the optimal parameter combination is greatly reduced, far better than the standard limit. The research confirms that the orthogonal design method can efficiently locate key control parameters with fewer test times, providing a scientific theoretical basis and engineering practice guidance for the optimal design, parameter setting and on-site debugging of the operating mechanism and transmission link of high-voltage circuit breakers.