[Purpose] Accurately identifying key and core technologies is of great significance for understanding critical technology domains and achieving technological breakthroughs. [Method] Building upon the definitions of key and core technology concepts, this study proposes a key and core technology identification method based on patent competitiveness index and Doc-LDA topic model. The metrics including topic strength, topic co-occurrence strength, and effective cohesion constraint coefficient is considered. [Results] Taking new energy vehicles as an empirical research example, a total of 10 key core technologies are identified, including fuel cell technology, solid-state power battery technology, high-efficiency high-density motor drive system, lightweight plastic and composite material technology, cellular communication technology, mechatronics coupling integration, multi gear transmission, vehicle operation technology, intelligent control technology, and autonomous driving technology. [Limitation] In the future, the scope of technical field analysis will be further expanded, aiming to discover universal principles and explore methods to refine the granularity of topics. [Conclusion] By utilizing the patent competitiveness index and the Doc-LDA theme model, the paragraph semantic relationship is considered and existing recognition methods are optimized.