The technology breakthrough capability is the main bottleneck that restricts latecomer enterprises from achieving full autonomy and the independent control of key core technologies. Existing research has inadequately addressed the formation mechanism of this capacity. This paper adheres to the “windows of opportunity-holistic innovation” adaptive perspective, and investigates the formation mechanism of the key core technology capability for latecomer enterprises using CRRC Zhuzhou Institute IGBT technology breakthrough as a case. The findings are summarized as follows：Firstly, the key core technology breakthrough evolves through a formation path of “craftsmanship system breakthrough capability→key products independently research and develop capability→product platforms construction capability→technological ecosystem govern capability”, the formation path demonstrate a spiral ascending process; Secondly, the formation of this capability is driven by strategic guidance force, collaborative cooperation force, open integration force, and resource assurance force; Thirdly, triggered by the windows of opportunity, latecomer enterprises have developed adaptive capabilities for key core technology breakthrough through holistic innovation responses. This study enriches the theoretical system of holistic innovation, advances the theory of technology breakthrough for latecomer enterprises, and offers insights into cultivating the key core technology breakthrough capability.