Use of integrated standards in today's economy is imperative to create efficient financial markets, improve resource allocation and reduce transaction costs. In the same vein, all countries must make a lot of effort to develop common standards. However, ethnic diversity in different parts of the world results in different interpretations and judgments from accounting standards and challenges a lot of convergence of standards. Therefore, studying and recognition of ethnic differences impact on interpretation of accounting standards in Iran, which consists of different ethnicities with diverse values ​​and characteristics, is considered important. However, ethnicity is influenced by external and internal variables, including individual characteristics (conservatism, gender and age, etc.) that should be considered in its impact on interpretation of accounting standards. Purpose of this study is to investigate intermediary effect of auditor’s conservatism on relationship between ethnicity and interpretation of probabilistic propositions in accepted accounting standards. For this purpose, the research was conducted by distributing the questionnaire among 228 members of charted accountants in 2017 and analyzed relevant responses. The findings showed that auditors' conservatism has an intermediary effect on the relationship between ethnicity and interpretation of probabilistic propositions in accepted accounting standards. This finding can be useful in understanding factors affecting the judgment of auditors and helping to improve the judgment of auditors