In response to the challenges of cumbersome model modification steps and low efficiency in the repetitive design process of gas springs, a parametric design method combining multimodal knowledge is proposed. This approach involves exploring the relationship between requirement index parameters and geometric control parameters while organizing the geometric control parameters and model variation relationships based on traditional parametric modeling methods. The requirement index parameters are used as system inputs, and a parametric modeling system is programmed based on multimodal knowledge by integrating formulas, design manuals, and standards. Taking the design of a single-tube gas spring as an example, the above design method was applied, and the Creo 2.0 platform was further developed using the Pro/Toolkit package to construct a parametric design system for gas springs. Validation results indicate that this method is both feasible and efficient, addressing issues in previous parametric design systems, such as difficulties in sourcing geometric control parameters and low design flexibility.