Objective To explore the effects of Tet1 protein on cell proliferation, the cell cycle and apoptosis, an inducible Tet1CD overexpression cell line was established. Methods A recombinant pTRE-Tight_Tet1CD_IRES_RFP_ RPBSA_ M2rtTA _ Puro plasmid was constructed, then the recombinant plasmid and the “ Sleeping Beauty” plasmid expressing a transposase were cotransfected into HEK293T cells using lipofectamine. The inducible stable 293T (Tet1CD) cell line was selected using puromycin. Tet1 protein expression was detected via western blot, and the 5hmC content in the genome was detected using DNA Dot Blot. The effect of Tet1CD protein on the cell cycle and apoptosis was detected using flow cytometry, and the effect of Tet1CD protein on cell proliferation was detected by cell counting. Results The HEK293T (Tet1CD) cell line with inducible Tet1CD expression was successfully established. Western blot and DNA Dot Blot assays showed increased amounts of Tet1CD proteins and increased 5hmC content in inducible cells. Flow cytometry result demonstrated that Tet1CD expression promoted apoptosis (P< 0. 05) and increased the proportion of cells in G2 phase (P< 0. 05). Cell counts showed that Tet1CD overexpression inhibited cell proliferation (P< 0. 0001). Conclusions Tet1 protein may inhibit cell proliferation by promoting apoptosis and delaying the cell cycle.