N-(2-hydroxy-3-trimethylamine) propyl chitosan chloride (HTCC) nanoparticles were prepared through two-step method using chitosan with low molecular weight and high degree of deacetylation. H of-NH2 of chitosan was replaced with quaternary ammonium salt groups to form HTCC. HTCC was further modified by ion sol-gel reaction with sodium tripolyphosphate, the reaction can be in the dispersion under the action of Span-80, and the ionic bonds formed between phosphate group of sodium tripolyphosphate and the amino group in HTCC main chain, well dispersed HTCC nanoparticles with a average diameter of 23.6nm were than obtained. The structure was characterized with fourier transform infrared spectrum (FTIR). When HTCC nanoparticles were applied to contact with staphylococcus aureus(S. aureus) and escherichia coli (E. coli), the results showed completely under the condition of antimicrobial resistance.