Abstract: Experiments were conducted to investigate the effects of early feed restriction on the lipid peroxidation，enzymatic antioxidant activity and ascites incidence of broiler under normal or low ambient temperature. Broilers were exposed to low ambient temperature to induce ascites syndrome. In experiment 1, the restricted chicks were fed 8 hours per day either from day 7 to day 14 or from day 7 to day 21, while the controlled chicks were fed ad libitum. In experiment 2, the restricted chicks were fed 80% or 60% of previous 24 hour feed consumption of full-fed controls for 7 days from day 7 to day 14, while the full-fed controls were fed ad libitum all through the experiment. Plasma malonilaldehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) concentration and ascites heart index (RV/TV ratio) were continuously surveyed. The results showed that low temperature significantly increased the plasma MDA concentration and decreased the plasma SOD and GSH-Px activity. The RV/TV ratio at week 5~6 and the ascites morbidity were significantly increased in low temperature treated broiler. Early feed restriction markedly decreased the plasma MDA concentration. The plasma SOD and GSH-Px activity of feed restricted broiler was markedly higher than that of the fed ad libitum broiler during late experimental period. All early feed restriction treating reduced ascites morbidity. The RV/TV ratio of feed restricted chicks was lower than that of the uncontrolled chicks on day 42. The results indicated that early feed restriction alleviated the lipid peroxidation, enhanced the enzymatic antioxidant activity and finally reduced the ascites morbidity of broiler.