Abstract: The mass line, as the lifeblood and fundamental working approach of the Communist Party of China (CPC), integrates Marxist historical materialism with traditional Chinese people-oriented thinking. Its practical forms have continuously evolved with the development of the times. Since the new era, in the face of new characteristics in party-mass relations and new requirements for party members and cadres to perform their duties, the people’s standpoint inherent in the mass line has gradually transformed into a guiding principle for party members and cadres to establish and practice a correct understanding of governance performance, achieving a paradigm shift from a macro political line to individual political norms. Based on the great practice of comprehensively strengthening party governance in the new era, this article aimed to sort out the transformation logic from the mass line to a correct understanding of governance performance from three dimensions: logical reasoning, core essence, and practical purpose, to explain the dialectical relationship of being consistent and advancing with the times, and to provide theoretical and practical guidance for party members and cadres to perform their duties in the new era. The research showed that a correct understanding of governance performance is the condensation and practical extension of the mass line in the new era. It not only continues the people-centered value standpoint but also provides new theoretical support for party building in the new journey.