ObjectiveTo investigate the preventive and therapeutic effects of Qingfei Paidu decoction (QFPDD) on acute lung injury (ALI) in mice and its underlying molecular mechanisms based on miRNA sequencing technology. MethodsTwenty-four 4-week-old male KM mice were randomly divided into a control group, a model group, and a QFPDD group (n = 8 per group). After one week of acclimatization, mice in the control and model groups were intragastrically administered ultrapure water (0.2 mL per dose), whereas mice in the QFPDD group were intragastrically administered QFPDD (1.6 g crude drug/mL, 0.2 mL per dose), twice daily for 8 consecutive days. On days 2–8, mice in the model and QFPDD groups were exposed to aerosolized lipopolysaccharide (LPS) solution (2.5 g/L, 4 mL per exposure) for 7 consecutive days. On day 9, blood was collected via the retro-orbital venous plexus under deep anesthesia, and lung tissues were harvested. Body weight and lung weight were measured, and the lung coefficient was calculated. Serum levels of inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were detected by ELISA. Lung histopathological changes were observed by HE staining of paraffin-embedded sections. miRNA expression profiles in lung tissues were analyzed using the Illumina HiSeq 2500 sequencing platform. Target genes of differentially expressed miRNAs were predicted using bioinformatics databases, and functional enrichment analysis of these target genes was performed using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Differentially expressed miRNAs were validated by reverse transcription quantitative real-time PCR (RT-qPCR). ResultsCompared with the control group, the model group showed a consistent body weight growth trend but a significantly increased lung coefficient (P < 0.01). ELISA results showed that serum levels of TNF-α and IL-6 were significantly elevated in the model group compared with the control group (P < 0.01), whereas QFPDD treatment significantly reduced serum TNF-α and IL-6 levels compared with the model group (P < 0.05). HE staining showed that, compared with the control group, the model group exhibited widened alveolar septa, massive inflammatory cell infiltration, partial alveolar expansion, and mild capillary dilation with congestion. In contrast, the QFPDD group showed only slightly widened alveolar septa and mild inflammatory cell infiltration compared with the model group. Intersection analysis of miRNA sequencing data identified 13 differentially expressed miRNAs common to both the model vs. control and QFPDD vs. model comparisons. Among them, 6 miRNAs (mmu-miR-203-3p, mmu-miR-181b-5p_R-1, hsa-miR-4286_R+1, mmu-miR-1843b-5p_L+1R-1_2, mmu-miR-22-3p, and mmu-miR-1964-3p) were significantly up-regulated in the model group (P < 0.05) and significantly down-regulated after QFPDD treatment (P < 0.05), showing a therapeutic reversal trend. GO analysis revealed that the target genes of the differentially expressed miRNAs were mainly enriched in biological processes such as RNA polymerase Ⅱ transcriptional regulation. KEGG analysis indicated that target genes were mainly enriched in signaling pathways including the mitogen-activated protein kinase (MAPK) pathway. RT-qPCR validation result for mmu-miR-203-3p was consistent with the sequencing analysis results. ConclusionQFPDD may exert preventive and therapeutic effects against ALI by regulating the expression of mmu-miR-203-3p and other miRNAs, thereby modulating inflammatory responses and the MAPK signaling pathway and participating in the pathological process of lung injury.