This study was conducted to investigate the effects of Honeysuckle extracts on serum hormones and antioxidant indexes of beef cattle under heat stress of high temperature environment in summer. Twenty healthy Jinjiang yellow cattle with body weight of (360±20) kg were divided into four groups with five in each group and one cattle per replicate. Honeysuckle extracts at 0(control), 0.2%, 0.4% and 0.6% were added in concentrates. The pretest lasted for 10 days, and the test lasted for 60 days. The results showed as follows: compared with control group, 1) body temperature in 0.2% and 0.6% groups were significantly declined on days 40 (P<0.05); there was no significant effects on daily gain (P>0.05). 2) Serum contents of triiodothyronine and thyroxine in experimental groups were increased, but serum cortisol content was declined. 3) Serum activities of superoxide dismutase, glutathione peroxidase and total antioxidant capacity in experimental groups were enhanced, but serum content of malondialdehyde was decreased. These results indicate that dietary supplementation of Honeysuckle extracts improve antioxidant capability, and relieve stress reaction of beef cattle, but had no significant effects on weight gain; the optimal level is 0.2% supplemented in concentrate considered all the indexes.