Abstract: Performance commitment has been more and more widely used in mergers and acquisitions (M&A). As important participants in the capital market, the protection of the minority investors' interests has become increasingly prominent. This paper takes the M&A events including performance commitments from 2008 to 2019, finding out that there is a significant tunneling effect in the failed performance commitments, which will seriously damage the interests of minority investors, thus supporting the agency view. Furthermore, the heterogeneity of performance commitment tunneling effect under different enterprises, M&A and performance commitment characteristics is tested; earnings management manipulation is important tools for listed companies to implement tunneling behavior by using performance commitment; external audit and internal supervision are effective tools to governance the tunneling effect. This paper enriches the research on the effectiveness of M&A performance commitment from the perspective of minority investors, provides practical significance for minority investors to judge performance commitment rationally, for regulators to formulate rules reasonably, and for administrations to simultaneously control the tunneling of performance commitment under opportunism motivation.