Abstract: Objective To investigate the influence of vitamin B₆ modification on enzymatic activity of ferric iron oxide nanozymes(IONzymes)and its inhibitory effect on oral Streptococcus mutans(S. mutans). Methods IONzymes was modified with vitamin B₆ by a solvothermal reaction. The morphology of IONzymes with vitamin B₆ modification(VB₆-IONzymes)was observed by electron microscope, and change of its catalytic activity was analyzed. Results Compared with the unmodified IONzymes, the volume of VB₆-IONzymes was greatly reduced and its peroxidase activity was significanly enhanced. Bacteriostatic experiment showed that VB₆-IONzymes had a significant ability to inhibit S. mutans, and can significantly promote the inhibitory effect of 1% H₂O₂ on the S. mutans biofilm formation. Conclusion Vitamin B₆ modification not only improves the enzymatic activity of IONzymes, but also shows potential application value in preventing dental caries.