Abstract: Objective To build an in vitro neonatal rat epithelial tissue culture system, to detect the expression level of DNA methyltransferase(Dnmt) and relevant miRNA in the cultured tissues, and to investigate related mechanism of induction effect of TGF-beta during colon tissue culture. Methods We applied 3-days-old SD rat's intestinal tissues to build the in vitro tissue culture system and observed the growth state, added 10ng/ml TGF-beta in culture system to induce the growth of cultured tissues. The tissues from different time were collected in the experiment and the morphological change of the tissues was observed by HE staining through microscope. The expression levels of DNA methyltransferase and related miRNA were detected by reverse transcription (RT)-PCR. Results Slices of the tissues from different time were fixed, embedded and stained with Hematoxylin and Eosin. The morphology of the cultured tissues was changed as the extension of the culture time and the epithelial structure gradually disintegrated. RT-PCR results showed that after treated with 10ng/ml TGF-beta, the expression levels of Dnmts and relevant miRNA were abnormal; Dnmts expression were up-regulated or down-regulated; after TGF-β and 5-Aza-dC interference, the express level of Dnmts couldn't be detected; meanwhile the relevant miRNA expression level was up-regulated, even close to untreated status. Conclusion TGF-beta could influence the growth of colon tissues, lead to the abnormal expression levels of Dnmts and relevant miRNA; 5-Aza-dC inhibits the expression of Dnmts and regulates the abnormal expression of miRNA.