With the accelerated improvement of the global ESG governance system and the implementation of the new standards for sustainable information assurance in China, the report of sustainable information assurance has become a key carrier for enterprises to gain market trust. However, at present, the assurance market is dominated by accounting firms and other third-party professional organizations, and there are significant differences between them in terms of report style and content, which not only affects the comparability of report quality, but also is difficult to adapt to the unified requirements of standards and cannot meet the diversified needs of the market. To this end, taking the Sustainable Information Assurance Business Standard No. 6101 Basic Standards (Trial) as the core guidance, this paper compares and analyzes the differences between the assurance reports of accounting firms and other third-party professional institutions, focusing on revealing their differences in assurance procedures and substantive issues, assurance standards and scope, assurance level and conclusion, report structure and style, and identifying the adaptation gap between the existing reporting elements and the requirements of the standards. Further reconstruction of the framework of the core elements of the sustainable information assurance report suitable for the situation in China aims to provide practical guidance for the two types of institutions to standardize the implementation standards and improve the quality of the report, and at the same time improve the information content of the enterprise’s sustainable information assurance and provide strong support for stakeholders’ decision-making.