High biodiversity can mitigate the negative impacts of global change factors (GCFs) on differing ecosystem functions captured in multifunctionality. However, multiple GCFs occurring simultaneously may diminish the positive effects of high biodiversity on multifunctionality. Arbuscular mycorrhizal fungi (AMF) play a crucial role in determining ecosystem functionality, yet it remains unclear whether AMF alleviate the negative impact of multiple GCFs on ecosystem multifunctionality. In this study, we conducted a microcosm experiment to explore the role of AMF in maintaining ecosystem multifunctionality under multiple GCFs. We found that ecosystem multifunctionality under high AMF diversity was greater than under low AMF diversity under multiple GCFs. Notably, AMF diversity significantly improved plant growth simultaneously. While AMF inoculation significantly influenced soil functions, the diversity of AMF showed limited effect on soil functions. Our findings emphasize the importance of conserving AMF diversity to maintain ecosystem functionality.