Neutrophil extracellular traps (NETs) and circulating cell-free DNA (cfDNA) are pivotal in driving excessive inflammation and organ damage during sepsis, with their levels correlating positively with sepsis severity in both patients and murine models. Despite the ability of deoxyribonuclease I (DNase I) to degrade NETs and cfDNA, its short half-life and rapid degradation limit its therapeutic effectiveness. To address this challenge, we developed a methyl-branched liposome fused with a red blood cell membrane for the systemic delivery of DNase I (DNase I/Rm-Lipo). The efficacy of DNase I/Rm-Lipo was evaluated in the stimulated immune cells and septic model. The data confirmed that DNase I/Rm-Lipo efficiently removed excess NETs and cfDNA in activated neutrophils. Following injection, DNase I/Rm-Lipo exhibited an extended circulation time, effectively suppressing neutrophil activation and regulating macrophage polarization to mitigate inflammation and prevent organ dysfunction in septic mice. These findings highlight the therapeutic potential of DNase I/Rm-Lipo as a promising candidate for sepsis management by targeting the degradation of NETs and cfDNA.