Blast lung injury is a high-energy trauma with high mortality for explosion victims. A treatment for blast lung injury is still lacking. The aim of this study was to observe the efficacy and mechanism of peritoneal dialysis combined with glucocorticoids (GC) in the treatment of blast lung injury in rats. Rats were randomly divided into five groups: control, sham, GC, peritoneal dialysis (dialysis for short), and dialysis + GC groups. All rats were injured by a biological shock tube-I. The lung water levels in the dialysis group and dialysis + GC group were significantly lower than that in the control group at 6 and 24 h after blast injury. The oxygenation index, forced vital capacity, maximum midexpiratory flow, and functional residual capacity of rats in the dialysis and dialysis + GC groups were significantly higher than those in the control group. The serum levels of interleukin (IL)-1β, IL-6, tumor necrosis factor- α, monocyte chemoattractant protein-1, C-reactive protein, and IL-10 in the dialysis and dialysis + GC groups were significantly lower than those in the control group. Genome-wide mRNA microarray results showed that the aquaporin 1 level in the lung tissue of the dialysis group was 6.67 times higher than that in the control group. Early peritoneal dialysis can attenuate pulmonary edema and inflammation, and protect acute lung injury after blast injury.