Abstract: To achieve comprehensive optimization of performance, reliability, and economy of aviation welding products and address the challenges of strong reliance on experience, poor stability, and lack of quantitative design in traditional process specification formulation, a construction method of process specification based on knowledge-driven and trade-off design was developed. By breaking through the experience-centric paradigm, a three-in-one structural model of welding process specification integrating structure, technical elements, and semantics was proposed, which achieved the formal encapsulation and digital empowerment of process knowledge. Meanwhile, a specification verification method integrating design of experiments(DOE) and statistical process control(SPC) was established. Through the quantitative analysis of dispersion and process capability index, the scientific solidification of key process parameter thresholds was realized. Case application shows that this method provides a systematic theoretical model and support for the intellectualization and standardization of welding process specification of aviation products, effectively promoting the transition of process design from being experience-driven to being knowledge-driven.