Abstract: The aim of this study was to investigate the effect of manganese on the hepatic apoptosis in cocks. 400 fiftyday old Hyline brown cocks were randomly divided into four groups. The 0, 600, 900 and 1 800 mg·kg1 MnCl2 were respectively added into the basic forage to establish the subchronic manganism model. After 30, 60 and 90day treatment, the livers in every group were collected to observe hepatic morphological change and detect hepatic apoptosis index and the transcription level of Fas mRNA. Results showed that among 90day treatment groups, the liver form the highest dose group took on the typical morphologic changes of apoptosis compared with the corresponding control group, and the number of the apoptotic cells gradually increased with the increase of the manganese dose. The transcription level of Fas mRNA also took on the doseeffect relationship at different treatment time.