Financing constraints is a key factor which influences corporate R&D investment. Under the background of supply-side reform, this paper takes the supply of accounting information elements and the supply of ownership system elements as the entry point, and aims to seek the path of easing financing constraints of R&D. We uses the data of Chinese listed firms between 2010 and 2014 as the research sample, and find accounting information quality has significantly eased corporate financing constraints of R&D, and this effect is closely related to corporate ownership structure. We find the more dispersed corporate ownership and the higher the equity balance degree, the more obvious the mitigative effect of accounting information quality on financing constraints of R&D; compared with state-owned firms, the mitigative effect of accounting information quality on financing constraints of R&D is more significant under non state-owned firms. This research has certain practical guiding significance for enterprises to alleviate R&D financing constraints problem, and also provides empirical experience for micro enterprises to carry out supply-side reform.