The report to the 20th National Congress of the Communist Party of China clearly states that high-quality development is the primary task in building a modern socialist country in all respects. The key to achieving high-quality development lies in scientific and technological innovation, which serves as the primary driving force for development. This study constructs a composite system of R&D investment and economic development. It uses a coordination degree model to measure the coordination degree of this system. The measurement covers nearly three decades of national data from 1991 to 2020 and provincial data from 2011 to 2020. The study provides a comprehensive depiction and analysis of the evolving trends and distribution of the interaction between R&D investment and economic development in China. The study aims to provide decisionmaking references for optimizing the allocation of scientific and technological resources in China from the perspective of high-quality development.