Abstract: In order to investigate the change rules of body temperature, pulse and respiratory rate of dairy cows in different conditions of temprature-humidity index（THI）, 900 Holstein dairy cows were taken as the research objects. The body temperature, pulse, respiratory rate of cows and the dry and wet bulb temperature of the cow house were continuously measured in Bengbu City during the hot time of the year（from July 19 to September 16, 2022）, and THI was calculated to study the correlation between THI and body temperature, pulse and respiratory rate of cows. The results showed that when 69≤THI≤79, the body temperature fluctuated between 39.2 ℃ and 39.3 ℃; the pulse increased from 62 times/min to 74 times/min, and the respiratory rate increased from 57 times/min to 74 times/min. There was no significant difference in body temperature of cow between THI at 79 and THI at 69（P＞0.05）, but the difference in the pulse and the respiratory rate was significant（P＜0.01）. When 79＜THI≤89, the body temperature of cows increased from 39.3 ℃ to 39.6 ℃, the pulse increased from 74 times/min to 77 times/min, and the respiratory rate increased from 74 times/min to 81 times/min. There was no significant difference in the body temperature, pulse and respiratory rate of cow between THI at 89 and THI at 79（P＞0.05）. When 89＜THI≤93, the body temperature of cows increased from 39.6 ℃ to 40.0 ℃; the pulse fluctuated from 77 times/min to 78 times/min, and the respiratory rate increased from 81 times/min to 83 times/min. There was a significant difference in the body temperature of cow between THI at 89 and at 79（P＜0.01）, but there was no significant difference in the pulse and respiratory rate（P＞0.05）. The results showed that when 69≤THI≤79, the pulse and respiration rate were correlated with THI, but the body temperature was not significantly correlated with THI. When 79＜THI≤89, the body temperature, pulse and respiration rate of cows were not significantly correlated with THI. When 89＜THI≤93, the body temperature of cows was correlated with THI, but the pulse and respiratory rate were not significantly correlated with THI.