Bacterial biofilms are closely associated with persistent infections. E?ective penetration of antibacterial drugs is necessary for the treatment of bacterial biofilms. In this study, a nanoparticle-stabilized Pickering emulsion with strong permeability and high antibacterial activity was fabricated for the treatment of bacterial biofilms. This Pickering emulsion was composed of clove oil core and chitosan nanoparticles. The clove oil was used as an antibacterial agent, and the chitosan nanoparticles provided a positively charged shell, which could interact with the negatively charged extracellular matrix to achieve strong penetration through bacterial biofilms. Both of the chitosan nanoparticles and the Pickering emulsion with narrow size distribution and good dispersity were prepared successfully. The average size of chitosan nanoparticles was 590.30±3.90 nm with 0.125±0.003 of polydispersity index (PDI), and the average Zeta potential was 15.60±0.40 mV. The average size of the Pickering emulsion was 2312±53 nm with 0.137±0.013 of PDI, and the average Zeta potential was 26.45±0.55 mV. The experiments of bacterial biofilms penetration and antibacterial test revealed that the Pickering emulsion could effectively penetrate the bacterial biofilms and kill bacteria. Besides, the cytotoxicity test in vitro showed that the Pickering emulsion had good biosafety. All these results indicated that the Pickering emulsion had promising prospects for the treatment of persistent infections associated with bacterial biofilms.