Based on the financial data of Chinese listed companies from 2000 to 2014, this paper investigates the effect of collateral and accounting information quality on financial constraints. The result shows that increasing the collateral and improving accounting information quality can reduce the financial constraints. Different from the prior studies, this paper, after grouping according to accounting information quality, also finds that collateral value has a lower impact on financial constraints for the firms with higher accounting information quality, while in the group with lower information quality, a higher collateral can significantly reduce financing constraints. Collateral and accounting quality have substitution effect on financing constraints. After further distinguishing the nature of property rights, this paper finds that the above effects do not exist for state-owned enterprises, whereas collateral and accounting quality still have effect on financing constraints for the non state owned enterprises.