Science and technology finance is an organic combination of "primary productivity" and "first boost", and undertakes the important mission of driving high-quality regional economic development. Based on the current background of the continuous advancement of China’s technology and finance integration, the article uses the panel data of a total of 285 prefecture-level cities in China from 2007 to 2016 as an example, using the double difference method (DID) for the first time to test the driving effect and promoting mechanism on economic growth of the pilot policy of combining science, technology and finance implemented by five departments such as the Ministry of Science and Technology and the People’s Bank of China in pilot areas. The results show that: First, the pilot policy of combining technology and finance can effectively promote the economic growth of the pilot areas, and this conclusion is robust; second, the pilot policy of combining technology and finance has significant regional differences in the economic growth of the pilot areas. The strongest is the eastern region that is followed by the central region, and the western region is the weakest. Third, further mechanism testing shows that the pilot policy of combining technology and finance can drive regional economic growth through the dual path of improving the level of regional technological innovation and promoting the rationalization of the industrial structure. In order to further promote the integration of technology and finance and improve the level of regional economic development, local governments should attach great importance to the positive externalities of the pilot policy of integrating technology and finance on regional economic development and actively apply for the construction of pilot cities. At the same time, differentiated pilot policies should be formulated in accordance with the local conditions and social conditions, vigorously improve the level of technological innovation and industrial structure rationalization, and give full play to its intermediary role in regional economic growth.