In view of the reality of “new infrastructure” and “cost reduction”, this paper selects 31 provincial data of China from 2000 to 2018 to empirically analyze the impact of regional network access, financial development and corporate financing costs. The results show that: first, there is a positive correlation between the accessibility of regional transportation networks and financial development, but a negative correlation between the accessibility of communication networks with financial development, i.e. the hardware construction of regional communication network is positively correlated with financial development, and there is an inverted U-shaped relationship between the two, while the use level of communication network software is negatively correlated with financial development. Second, there is a negative correlation between the regional financial development with corporate financing expenses. Third, there is a negative correlation between regional transportation network access with corporate financing expenses, and a longterm and short-term inconsistency in the impact of communication network access on corporate financing expenses based on the financial development constraints. The hardware construction of communication network has a squeezing-out effect on corporate financing in the short term, and the soft usage of communication network has an indirect competition effect on corporate financing in the long run. There is a negative correlation between technological innovation and enterprise financing cost under network access, and there is an inverted U-shaped relationship. It is necessary to pay attention to the short-term and long-term effects in promoting new-type infrastructure investment and cost reduction.