Abstract: The experiment was conducted with the objective of examining the effect of dietary high copper on the cell cycle and apoptosis of liver in chickens by the methods of flow cytometry (FCM) and TUNEL. 420 one-day-old Avian chickens were randomly divided into seven groups based on diets as follows: control feed (11 mg/kg Cu) and high copper feed(100 mg/kg Cu as high copper group Ⅰ；200 mg/kg Cu as high copper group Ⅱ； 300 mg/kg Cu as high copper group Ⅲ; 400 mg/kg Cu as high copper group Ⅳ； 500 mg/kg Cu as high copper group Ⅴ； 600 mg/kg Cu as high copper group Ⅵ). All groups were treated for six weeks. By FCM, the percentage of hepatocyte apoptosis was found increased in high copper groups Ⅲ, Ⅳ, Ⅴ and Ⅵ when compared with that of control group. Also, the TUNEL staining of liver tissue showed that apoptosis cells were increased in high copper groups Ⅳ, Ⅴ and Ⅵ respectively. The G₀/G₁ phase of cell cycle of liver was much higher, and S, G₂ + M phases lower in high copper groups Ⅳ, Ⅴ and Ⅵ than in control group (P<0.05 or P<0.01).