Innovation is inseparable from the development of enterprise and the improvement of enterprises, and the improvement of innovation is inseparable from the supporting system. In the background of advocating supply-side reform in our country, this paper examines the adjustment of elements structure in the supply-side reform, by constructing models to analyze the need of money when enterprises decided to invest in innovation as well as how financial system affects their need. The result of the model shows that the interest rate of loan determinates whether the company decides to undertake technological innovation. Indirect financing market can stimulate enterprises’ RD direct financing market can promote R&D investment by adjusting the ratio between interest rate and riskless interest rate.