•Au-TNT generates O2 while releasing ROS under the action of ultrasound.•SDT-mediated Au-TNT has a killing effect on oral multi-species biofilm.•The SDT in a rat peri-implantitis model improves bacterial-induced inflammation.•Au-TNT has excellent physicochemical stability for further clinical application. Peri-implant infection caused by bacterial biofilm is the main reason for dental implant repair failure. The success of controlling infection depends mainly on eliminating bacterial biofilm. However, traditional medicine therapy is not practical due to the growth of bacterial resistance. Recently, antibacterial sonodynamic therapy (aSDT) activated by ultrasound has been recognized as an emerging strategy for treating biofilm infections. In this study, an activatable nanoplatform (Au-TNT) fabricated on the implant surface is proposed for aSDT. Au-TNT could rapidly produce O2 under ultrasonic irradiation, which could relieve the hypoxic microenvironment of biofilm and improve the anti-biofilm efficiency of aSDT. Furthermore, it could generate singlet oxygen (1O2) and hydroxyl radicals (OH), resulting in a powerfully high antibacterial capacity for both single and multi-species pathogenic biofilms as assessed by bacterial survival rate, cell membrane rupture, biofilm metabolism and thickness. Meanwhile, Au-TNT exhibited excellent antibacterial ability in vivo with a 3 logs CFU decreased compared to the control group. Interestingly, it also showed that Au-TNT downregulated inflammatory factor levels and promoted bone repair. Thus, this study provides a sonodynamic-catalytic nanoplatform for efficient biofilm eradication and peri-implant infection treatment.