Abstract: Objective To explore the effect of nifuroxazide on proliferation, migration, and invasion of thyroid papillary carcinoma cells. Methods BCPAP and TPC-1 cell lines treated with different concentration (0, 1.25, 2.5, 5, 10, 20 μmol/L) of nifuroxazide, respectively. Cell viability and proliferation of BCPAP and TPC-1 was evaluated by MTT and colony formation assay. Apoptosis analysis and cell nuclear changes were determined by staining with Hoechst 33258 and visualized by a fluorescence microscope after treatment with nifuroxazide. Western blot analysis was used to evaluate protein expressions of apoptosis and invasion of BCPAP cells treated (48 h) with nifuroxazide. Transwell assay was conducted to evaluate ability of cell migration and invasion. Results After being treated with nifuroxazide (0, 1.25, 2.5 μmol/L and 0, 1.25 μmol/L) for 24, 48, 72 h respectively, decreased proliferations of BCPAP and TPC-1 cell lines were not obvious ( P>0.05). However, treated BCPAP and TPC-1 cells with higher concentration respectively (5, 10, 20 μmol/L and 5,10 μmol/L) of nifuroxazide for 24, 48, 72 h, the inhibitory effects were significantly obvious ( P<0.05), and the inhibitory effects were increased in a CM(155mmconcentration- and time-dependent manner. The inhibition in proliferation of TPC-1 cell with nifuroxazide (2.5, CM)5 μmol/L) took effect from 72 h and 48 h ( P<0.05), respectively. Clone formations of BCPAP and TPC-1 cells were significantly inhibited after being exposed to nifuroxazide (2.5, 5 μmol/L) for 10 d ( P<0.05). Hoechst 33258 staining assay showed that nifuroxazide (10 μmol/L) treatment resulted in cell shrinking, nuclear fragmentation and formation of condensed nuclei with bright-blue fluorescence. After 48 h, the percentage of apoptotic cells of BCPAP and TPC-1 significantly increased respectively as the concentration of nifuroxazide with 10 μmol/L ( P<0.005). Pro-apoptotic protein CC-3 and Bax expression levels increased significantly ( P<0.05), and the expression of anti-apoptotic protein Bcl-2 decreased significantly （ P<0.05） in BCPAP cells after nifuroxazide-treatment (10 μmol/L) for 48 h. The percentage of migrations and invasions of BCPAP and TPC-1 significantly decreased ( P<0.05) in the presence of nifuroxazide (10 μmol/L, 48 h). Nifuroxazide (10 μmol/L) treatment significantly decreased the expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in BCPAP cells（ P<0.05）. Expression of MMPs family inhibitor-tissue inhibitors of metalloproteinase (TIMP)-2 increased ( P<0.05). Conclusions Nifuroxazide inhibits the proliferation of thyroid cancer cells BCPAP and TPC-1, induceds the cell apoptosis by up-regulating the expressions of CC-3 and Bax proteins in vitro, and blocks migration and invasion of cells in vitro by reducing protein expressions of MMP-2 and MMP-9.