Using the weighted average of distance between firms and ecological areas, including national nature reserves, A-class scenic spots, national forest parks, and rivers, as a measure of biodiversity risk, we find that biodiversity risk leads to higher audit fees. Specifically, firms facing higher biodiversity risks pay higher audit fees and produce lower quality financial reports. In examining the mechanisms, we find that firms facing high biodiversity risk may experience higher reputational risks, litigation risks, and financial risks due to associated physical and transitional risks, and these business risks will translate into audit risks. The robustness of our findings is ensured by employing the difference-in-differences (DID) method, two-stage least square (2SLS) method with instrumental variables. Moreover, firms that be certain to disclose their biodiversity impacts in their sustainability reports, focus on social responsibility (CSR), and continue to green innovation and development (R&D) will reduce their biodiversity risk. Further analysis shows that this effect is particularly significant among state-owned enterprises (SOEs) and non-Big 4 audited firms. In summary, our study highlights the significant impact of biodiversity risk on auditor fees.