Objective To explore the role of miR-204-3p in silicosis epithelial-mesenchymal transition，and to elucidate the mechanism by which miR-204-3p affects silicosis fibers by regulating silica dust-induced alveolar epithelial mesenchymal transition process in rats.Methods Forty SD rats were randomly divided into four groups: control group, silicosis model group, miR-204-3p control group (miR-204-3p-NC group), and miR-204-3p Activator group. HE staining and Masson staining were used to observe the pathology of the lung tissue damage in rats; real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the relative expression levels of miR-204-3p and EMT marker genes in the lung tissue of rats in each group. Real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the relative expression levels of miR-204-3p and EMT marker genes in the lung tissues of rats in each group, and Western blot was used to detect the protein expression levels of EMT-related markers in the lung tissues of rats in each group.Results Compared with the control group, the alveolar structure was damaged, interstitial fibrosis of lung septa, and mesenchymal marker expression was elevated in the silicosis model group (P<0.05); compared with the miR-204-3p-NC group, the alveolar structure was more complete, the EMT process was alleviated, the fibrosis was improved, and the mesenchymal marker expression was reduced in the miR-204-3p Activator group (P<0.05). Conclusion Free silica dust can induce epithelial mesenchymal transition in rat lung tissues. overexpression of miR-204-3p has an intervening effect on the epithelial mesenchymal transition process of free silica dust-induced rat lungs, which is expected to affect the fibrosis process of silicosis.Conclusion Free silica dust induces epithelial mesenchymal transition in rat lung tissue. Overexpression of miR-204-3p has an intervening effect on the process of epithelial-mesenchymal transition induced by free silica dust in rats, which is expected to affect the process of silicosis fibrosis.