With the revision of the Company Law and its supporting rules, listed companies will now have audit committees fully take over the responsibilities of the supervisory board, becoming the sole supervisory body in corporate governance. However, the operation of audit committees presents not only a logical dilemma of self-supervision but also numerous ambiguities in practical matters such as duty fulfillment, member selection, recusal voting, and meeting convening. The goals and effectiveness of supervision likewise remain unclear—issues that are closely linked to informal hierarchies, insufficient internal motivation, and limited access to decision-making information. The immediate cause of these difficulties lies in the legislative transfer of the supervisory board’s functions in their entirety to audit committees. Yet, the deeper reason lies in the longstanding vagueness of the internal supervisory logic and objectives, compounded by the misalignment of supervisory targets and an inherently unreasonable distribution of supervisory powers within the former system. Given that the replacement of the supervisory board by audit committees has become a fait accompli, it is essential to further refine the institutional mechanism of audit committees. Looking ahead, audit committees in listed companies should be positioned as an external expert supervisory body, with its supervisory focus centered on ensuring legality and regulatory compliance in corporate governance. Its work should emphasize ex-ante supervision and financial oversight, concentrating on the construction of governance mechanisms and risk monitoring. If future revisions of the audit committee system are considered, the scope of its supervisory responsibilities should be narrowed—particularly with respect to matters that the former supervisory board was ill-suited to handle or had no need to assume. In terms of composition, standards should be established for the professional knowledge and competence of committee members; even employee directors should possess accounting or legal backgrounds. Furthermore, procedural rules should be refined, and the remuneration system for committee members should be optimized to achieve effective institutional incentives. Finally, when pursuing accountability for committee members, emphasis should be placed on whether the breached duty concerns the lawful and compliant governance of the company. Responsibility should be precisely attributed to different members according to their respective duties, thereby ensuring that audit committees can function as an effective and professionally credible supervisory body within the framework of modern corporate governance.