Technology standardisation is becoming a strategic initiative for globalised enterprises committed to innovation and development. However, the role of Technical Standards Alliance (TSA) as the primary method of participating in technology standardisation and the relationship between alliance enterprises for innovation benefits remains unclear, which leads to the partial failure of enterprise standardisation and innovation. This study constructs a research model based on coopetition theory to explore the mediating mechanism and boundary conditions of the Standards Alliance Coopetition Relationship (SCR) affecting enterprises' Technology Innovation Performance (TIP). The researchers conducted a questionnaire survey involving 542 standards alliance participating enterprises in China. The results of the regression analysis and self-help test reveal that (1) SCR positively affects enterprises' TIP; (2) Knowledge Acquisition (KA) and Routine Updating (RU) act as both a two-path mediator and a chain mediator between SCR and the enterprises’ TIP; and (3) Cognitive Proximity (CP) among alliance enterprises positively moderates the relationship between SCR and KA, and SCR and RU. These findings contribute theoretically to the literature on technology standardisation and address the research gap on how enterprises can effectively enhance their TIP through participation in standardisation. Finally, the study provides significant managerial implications for enterprises to construct robust standard alliance coopetition relationships, strengthen knowledge acquisition, and enhance routine updating.