This paper examines the impact of shared auditors on the implicit leverage behavior of A-share listed companies from 2010 to 2022, with a focus on knowledge spillovers. The results show that a higher degree of shared auditors significantly inhibits leverage manipulation behaviors. This inhibitory effect strengthens as the degree of shared auditors increases. Mechanism tests demonstrate that shared auditors curb leverage manipulation by improving internal controls, enhancing information disclosure quality, and improving audit efficiency. Heterogeneity analysis reveals that shared auditors are particularly effective in curbing leverage manipulation in firms with high information transparency. These findings offer valuable insights into addressing corporate debt concealment through external supervision.