Abstract: On enhancing the professional competencies of internal auditors in state-owned enterprises (SOEs) under the background of big data, by analyzing the current status of internal auditors' professional competencies and the challenges they face, it is pointed out that they not only need to possess traditional auditing skills but also have certain big data processing and data analysis skills. Based on the characteristics of the internal audit work in the context of big data, the paper proposes the professional competencies that internal auditors should possess. Further, it puts forward countermeasures for enhancing the professional competencies of internal auditors through a case study of an audit project in an offshore engineering company. This study provides effective guidance and suggestions for improving the professional competencies of internal auditors.