Social trust is an important informal system that not only promotes macroeconomic development, but also affects microeconomic behavior. Taking the A-share listed companies in China from 2007 to 2017 as a research sample, the paper studies the influence of social trust on the accounting information comparability. The study finds that under the same conditions, accounting information comparability increases with the increase of social trust; after distinguishing the nature of property rights, it is found that the promotion of social trust to accounting information comparability is more obvious in non-state-owned enterprises; further the promotion of social trust to accounting information comparability is less obvious in the company with higher internal control, higher institution investor shareholding ratio and higher analyst following number, verifying the logic of social trust to ease the agency problem. In addition, through the mediation effect test, earnings management plays a partial mediating effect between social trust and accounting information comparability, that is, social trust can improve the accounting information comparability by reducing earnings management.