To investigate the anti-oxidative ability and Hsp70 gene expression in hyperthermia induced mice, Kunming male mice, 5~6 weeks old, were divided randomly into seven groups, one control group and six experimental groups. Mice in experimental groups were treated with high temperature (41 ℃，2 h). Organ index, antioxidant enzyme activities, and Hsp70-1, Hsp70-3 gene expression in liver were determined at 0, 2, 6, 12, 24 and 48 h after heat stress. The results indicated there was no significant difference in organ index and serum GSH between the experimental groups and the control, and SOD and MDA level in serum and liver increased significantly after heat stress (P＜0.05). In serum, SOD levels at 0 h and 6 h were significantly higher than those in the control (P＜0.05), and at 24 h and 48 h, there was no significant difference (P＞0.05); MDA level at 6 h was the highest, which was significantly higher compared with the control (P＜0.05), and at 24 h there was no significant difference (P＞0.05). In liver, SOD activities at 6 and 24h were significantly higher compared to the control (P＜0.05), and there was no significant difference at 48h (P＞0.05); MDA level was the highest at 0 h, which was significantly higher compared with the control (P＜0.05), and there was no significant difference at 6 h (P＞0.05); and GSH level was also the highest at 0 h, which was significantly higher compared with the control (P＜0.01). Gene expression of Hsp70-1 at 0, 2, 6, 12 and 24 h were significantly higher than those in the control group (P＜0.01), and no significant difference was detected at 48 h (P＞0.05). Gene expression of Hsp70-3 at 0, 2, 6 and 12 h significantly higher than those in the control group (P＜0.01), and no significant difference was detected at 24 and 48h (P＞0.05). In conclusion, acute heat stress resulted in the increased SOD and MDA levels in serum and liver, and the increased expression of Hsp70 genes, and all these indexes were almost restored to the control level at 48 h after heat stress.