To elucidate the effects of Zearalenone(ZEA) on proliferation and cell cycle of cultured thymic epithelial cells in mice,trypan blue staining and flow cytometric analysis were performed.At the concentrations from 1 to 25 mg/L,ZEA displayed a significant inhibitory action to proliferation of thymic epithelial cells in its dose-and timedependent manner.Higher doses(10-25 rag/L)ZEA could induce a profound increase in G2/M phase with arrest of thymic epithelial cells in the G2/M phase in a dose-dependent manner.In conclusion,ZEA could be assumed that there were toxic effects on the thymie epithelial cells of mice in vitro.