Abstract: R&D intensity can usually reflect the development of science and technology in a country(organization)or a region directly, and it has become an important reference when governments and international organizations formulate science and technology strategies. However, R&D intensity is often misused and misunderstood in the formulation of science and technology planning and monitoring of science and technology activities. In order to promote the scientific understanding and correct use of R&D intensity, and to explore the underlying factors that affect R&D intensity, this study provides multiple analytical perspectives and systematic evidence for the indicator of R&D intensity. It suggests that regional differences and industrial structure characteristics should be fully considered when setting the R&D intensity goal in science and technology policy planning.This article first reviews the origin and development of the R&D intensity, and analyzes its application and limitations in industry classification and national science and technology policy formulation. Secondly, the trend analysis method is used to analyze the change of China's R&D intensity from 1995 to 2020, and to explore the growth law of R&D intensity.Finally, the article analyzes the factors affecting R&D intensity from the two aspects of regional and industrial structure, in order to provide a theoretical basis for improving R&D intensity.The main findings of the study are:(1) The growth rate of national(or organization) R&D intensity usually slows down after reaching 2%, and it is difficult to exceed 3%. The growth law of China's R&D intensity is in line with general international experience;(2) Industrial structure is an important factor affecting the increase of China's R&D intensity.China's primary industry gross output value accounts for a relatively high proportion of GDP, and yet the R&D intensity of high-tech industries is still low, which leads to a low overall R&D intensity in China. The level of industrial development affects the R&D intensity, and the vigorous development of knowledge-intensive industries can effectively drive the increase in R&D investment;(3) There is a regional imbalance in China's R&D intensity. R&D intensity of the eastern provinces has reached the level of an innovative country, but it is not enough to drive the overall increase of China's R&D intensity. It is difficult for countries(or organizations) with unbalanced economic development in the region to increase R&D intensity. The uneven regional distribution of scientific and technological innovation resources results in the greatly varied level of scientific and technological development in different regions, which affects the overall R&D intensity.By analyzing the connotation, characteristics and influencing factors of R&D intensity, it is found that to blindly pursue numerical values of R&D intensity is unreasonable. The general development law of the R&D intensity must be followed, fully considering China's economic scale, industrial structure, and regional differences. The national(or organization) or regional R&D intensity improvement path should be designed from the perspective of improving industrial structure and upgrading and promoting regional balanced development. Finally, this research suggests promoting the transformation of industries in remote areas and encouraging the development of R&D intensive industries be accorded the top priority.
Key Words: R&D intensity; industry structure; regional difference