Key & core technology and key & core technology enterprises have become widely used concepts in the process of government promoting scientific and technological innovation and investment situations participating in scientific and technological investment. However, the understanding of the concept of key & core technology and key & core technology enterprises from all walks of life is still not clear enough, which is not conducive to the smooth development of theoretical research and practical work. Based on the basis of analyzing the key & core technology and key & core technology enterprises in the national discourse system and the folk discourse system, along the logical thinking of "focus on the subject - focus on the object - focus on the purpose - mechanism decomposition", the connotation and extension of key & core technology and key & core technology enterprises was extracted, and the standards to be met by the noteworthy key & core technology enterprises with state and investment situations were summarized. A solid theoretical foundation for better theoretical research and practical work of cultivating key & core technology enterprises is constructed. In addition, the concepts related to key & core technology are differentiated and analyzed, such as disruptive technology, cutting-edge technology, and neck technology, to avoid confusion.