Domestic demand is the fundamental factor propelling China’s economic growth and an essential prerequisite for satisfying the increasing aspirations of the populace for a better quality of life. Nevertheless, the capital market’s challenging financing environment has resulted in the frequent occurrence of enterprise investment and financing maturity mismatch issues, despite the ongoing efforts to increase the scope and efficacy of enterprise investment. Thus, we choose to examine the effects of mixed ownership reforms on investment and financing maturity mismatches within Chinese Shanghai and Shenzhen A-share state-owned listed companies from 2013 to 2022. The findings indicate a significant negative correlation between the reform level and short-term lending and long-term investment. This relationship mitigates maturity mismatch by easing financing constraints and lowering agency costs. The inhibitory effect is particularly evident in state-owned enterprises characterized by low levels of reform, smaller size, and those located in non-eastern regions. Furthermore, reforms contribute to the sustained value of firms over the long term. Consequently, the government should encourage the collaborative advancement of both state-owned and non-state-owned capital, while efficiently leveraging equity diversification to facilitate reforms tailored to the distinct characteristics of state-owned enterprises.