Objective To investigate the effects of arsenic on liver Fas/FasL expression in mice and to observe the antagonize effect of zinc. Methods Sixty health Kunming mice were divided into five groups according to their body mass: negative control group(no arsenic and no zinc), arsenic group(55 mg/L NaAsO2 solution), low dose zinc intervention group(55 mg/L NaAsO2 solution and 20 mg/L ZnSO4 solution), middle dose zinc intervention group (55 mg/L NaAsO2 solution and 40 mg/L ZnSO4 solution), and high dose zinc intervention group (55 mg/LNaAsO2 solution and 80 mg/L ZnSO4 solution). Everyday the solution was given by oral gavage at a dose of 0.02 ml/g body weight for six weeks. The expression of Fas/FasL in mice liver was examined by immunohistochemistry.Results With the amount of zinc increasing, the expression of both Fas and FasL in mice liver decreased gradually. The expression rates of Fas[83.33%(10/12), 50%(6/12)] and FasL[66.67%(8/12), 41.67%(5/12)]in low dose zinc intervention group and middle dose zinc intervention group, respectively, were different from the expression rate of Fas[8.33%(1/12)] and FasL[0.00%(0/12)] in the negative control group(all P < 0.05). The Fas expression rate of middle dose zinc intervention group[50%(6/12)] and the high dose zinc intervention group [25%(3/12)] was compared with the arsenic group[8.33%(1/12)], and the difference was statistically significant (all P < 0.01 ). The FasL expression rate of the middle dose zinc intervention group [41.67% (5/12 )] and the high dose zinc intervention group[16.67%(2/12)] was compared with positive control group[91.67%(11/12)], and the difference was statistically significant (all P < 0.05). Conclusions Arsenic can increase the expression of Fas and FasL in mice liver, and promote apoptosis in liver, zinc may antagonize the effect of arsenic.