Abstract: Regional innovation is the core force driving regional economic growth. Based on panel data from five provinces in northwest China from 2000 to 2021, this article constructs an intermediary effect model, Granger causality test, and threshold regression model to study the effect mechanism and path of fiscal technology expenditure on regional innovation and economic growth. Then it builds up a PVAR model to explore the long-term dynamic equilibrium relationship between different factors and economic growth. The research findings go as below: The fiscal technology expenditure promotes economic growth through regional innovation; Due to the existence of the threshold for human capital structure, the fiscal technology expenditure in the northwest region cannot effectively promote regional innovation at the current stage; There is a dynamic interaction mechanism between fiscal technology expenditure, regional innovation, human capital, and economic growth. Fiscal technology expenditure and regional innovation have a long-term stable positive effect on economic growth, while human capital structure has a significant short-term inhibitory effect on economic growth; the main factor of economic growth in the five provinces of northwest China comes from the effect of economic growth itself, followed by regional innovation and fiscal technology expenditure, the driving effect of human capital structure on regional economic growth is not significant.