To evaluate the antibacterial effect of multivalent silver ion carried by zirconium phosphate (ZP-Ag) both in vitro and in an experimental rat burn wound compared with that of sulfadiazine silver (SD-Ag). Firstly, the minimal inhibition concentration and the minimal bactericidal concentration of ZP-Ag to three different strains of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli) were compared with those of SD-Ag in vitro. Following this dressings containing the same mass of ZP-Ag or SD-Ag were applied to wounds in a rat burn model and their antimicrobial activity assayed. The inflammatory response of the wounds managed with the two kinds of dressings was compared. Both the minimal inhibition concentration and minimal bactericidal concentration of ZP-Ag to S. aureus, P. aeruginosa, and E. coli were two to four times lower than those of SD-Ag. In vivo ZP-Ag had a more effective antibacterial action inhibiting the growth of the above three bacterial strains under burn scar, compared with dressings made from the same mass of SD-Ag. Moreover, the antibacterial effect was unchanged after the ZP-Ag dressings were washed 20 times, while it dramatically decreased after the dressings with SD-Ag were washed 20 times. When covered by either regular or washed ZP-Ag dressings, the wounds showed integrity with no visible inflammatory reaction. However, various extents of inflammatory reactions on or around the wounds covered with regular SD-Ag dressing were observed. This study showed that dressings with ZP-Ag had a prominent and relative long-term antibacterial effect. ZP-Ag dressings could be an effective, low-cost management option for burn wounds.