Abstract:  Understanding correctly the relationship among science, technology and economy, and grasping the law of interaction between science and technology and economic development have an extremely important theoretical and practical significance. In fact, a large number of studies usually concentrate on the relationship among science, technology and economy independently, but they do not pay enough attention to the relationship between the “scientific & technical” interaction and economic development. Based on this background, this paper stands at the perspective of the separation of science and technology firstly, and uses the method of Granger causality test to explore the relationship among science, technology and economy. Then from the perspective of the interaction between science and technology, this paper uses the expanded Cobb Douglas production function, vector autoregressive model, impulse response function and variance decomposition method to measure the dynamic relationship of science, technology and economy output in China and demonstrate between the “scientific & technical” interaction and economic development. The scientific output data of this research comes from the Web of Science database and the Chinese CSCD database, and the technical output data comes from the China Statistical Yearbooks on Science and Technology (1991-2017), and the economic output data comes from the China Statistical Yearbooks(1991-2017), and the interaction between science and technology is obtained by product term of them. The conclusions show that scientific output is the Granger cause of technical output, and technical output is also the Granger cause of scientific output. It means that scientific output and technological output can promote each other. Scientific output is the Granger cause of economic output, but technical output is not the Granger cause of economic output. Compared with technological output, scientific output can better promote economic output. Economic output is not the Granger cause of scientific output, but in the long run, economic output is the Granger cause of technical output. Economic output promotes technical output better than scientific output. Further, the “scientific & technical” interaction is the Granger cause of economic output, but economic output does not constitute the Granger cause of the “scientific & technical” interaction. It shows that the “scientific & technical” interaction effect exists, and it plays an important role in promoting economic output. The economic development situation also has an important and unstable impact on the realization of the “scientific & technical” interaction effect.

Key words: scientific output, technological output, economic output;"Science-Technology", interactive perspective, vector autoregressive model