This study was conducted to investigate the effects of heat stress on endocrine hormone content, antioxidant enzyme activity and physiological and serum biochemical indices of beef cattle. Nine eight-month-old Jinjiang cattle with an initial body weight of (210±20) kg were fed in normal and heat stress periods. During the trials, temperature and relative humidity of cattle house were determined. The serum samples of beef cattle were collected, and then endocrine hormone content, antioxidant enzyme activity and physiological and serum biochemical indices of beef cattle were determined. The results showed as follows: 1)breathing frequency and diarrhea rate of beef cattle in heat stress period were significantly higher than those in normal period (P＜0.05); in heat stress period the rectal temperature of beef cattle was significantly increased on 20th day (P＜0.05), and then gradually recovered to normal. 2)Compared with normal period, triiodothyronine (T₃) content in serum was lower significantly (P＜0.05), but thyroxine (T₄) content was not changed (P＞0.05); cortisol (COR) content was significantly increased on 20th day (P＜0.05), and then gradually recovered to normal; the glucose (GLU) content in serum was decreased by 41.55% on 60th day (P＜0.05); the activities of superoxide dismutase (SOD) and alkaline phosphatase (ALP) in serum were significantly lower on 40th day (P＜0.05), but the content of malondialdehyde (MDA) and the activity of lactate dehydrogenase (LDH) were significantly increased (P＜0.05). These results indicate that high temperature and high humidity induce heat stress of beef cattle, and heat stress can enhance the rectal temperature and increase the content of cortisol, and decrease the contents of T₃ and glucose. However, the rectal temperature and endocrine hormone content of beef cattle would gradually recover to normal with the extension of heat stress time.