As a crucial informal institutional mechanism, corporate integrity culture significantly influences audit pricing decisions. Using data from A-share listed companies in China’s Shanghai and Shenzhen stock exchanges (2013—2023), this study empirically examines how corporate integrity culture affects abnormal audit fees. The findings demonstrate that an integrity culture significantly reduces abnormal audit fees, a conclusion that remains valid after controlling for endogeneity and conducting multiple robustness tests. Mechanistic analysis reveals that integrity culture suppresses abnormal audit fees by enhancing internal control effectiveness, mitigating operational risks, and improving information transparency. Further research indicates that the inhibitory effect of integrity culture on abnormal audit fees is more pronounced in companies with higher accounting conservatism, those operating in regions with advanced legal frameworks, and firms with high client importance. This paper not only expands the research on the economic consequences of corporate integrity culture but also provides empirical evidence for auditors risk assessment and audit pricing decisions.