Objective : To investigate the role of lncSIL in transforming growth factor-β1(TGF-β1)-induced alveo- lar epithelial interstitial transformation (EMT) and its related signaling pathways . Methods : Western blot was used to detect the effect of lncSIL silencing on the expression of E-cadherin ( E-cad) , alpha-smooth muscle actin ( α- SMA) and Collagen I (Col I) in the process of EMT induced by TGF-β1 . LncSIL interacting proteins were ana- lyzed by RNA pulldown . Western blot was used to detect the effect of overexpression or silencing of lncSIL on the expression of its target gene enhancer of zeste homolog 2 (EZH2) and its downstream factors P21 and cyclin-de- pendent kinase 6 (CDK6) . Flow cytometry was used to analyze the effect of lncSIL on cell cycle progression . Results: After lncSIL silencing , the expression of α-SMA and Col I increased , the expression of E-cad decreased . RNA pulldown assay showed that EZH2 was the target protein that interacted with lncSIL , and the expression of EZH2 increased after silencing lncSIL , the expression of EZH2 downstream gene P21 decreased , CDK6 increased . Flow cytometry showed that the number of cells in S phase significantly increased . When lncSIL was overexpressed , the expression of EZH2 and CDK6 was down-regulated , the expression of P21 was up-regulated , and the number of S phase cells significantly decreased . Conclusion LncSIL inhibits TGF-β1-induced alveolar epithelial cell mesen- chymal transition by negatively regulating EZH2/P21 /CDK6 signaling pathway to inhibit cell cycle progression .