Organizational Ethical Self-Interest Climate (OESIC), a type of Organizational Ethical Climate (OEC) that exists widely in various organizations, plays an important role in unethical behaviours. Unfortunately, there is still little in-depth research on the effect of OESIC on Unethical Accounting Behaviour (UAB) and its related mechanism. This paper aims to explore the impact of OESIC on UAB with two different motivations i.e., Unethical Pro-Self Accounting Behaviour (UPSAB) and Unethical Pro-Organizational Accounting Behaviour (UPOAB). In addition, this paper studies the moderating effect of Confucian ShiZhong Thinking (CSZ Thinking), a typical characteristic of the Chinese people. In this paper, questionnaire data from 258 Chinese accountants at different professional levels were collected. A regression model was used to analyse and test the collected data. The results indicate that OESIC is positively correlated with UAB, and the effect of OESIC on UPSAB is more significant than the effect on UPOAB. CSZ Thinking weakens the positive impact of OESIC on UPSAB and UPOAB. This paper expands the research scope of OESIC into the accounting field and the Chinese context, which is helpful to better understand the relationship among OESIC, UAB and Confucian ShiZhong Thinking. This paper can enlighten organizational managers to consider the role of informal management control systems in restraining UAB and to pay attention to the two types of UAB with different motivations, especially UPOAB.