Abstract: Objective To observe the changes of heart rate (HR) and mean arterial pressure(MAP)after immediate cooling therapy (ICT) in rats with superficial second-degree scald burn in hot and humid environment, and assess the effect of the cooling dressing materials. Methods Twenty-four Wistar rats were randomized equally into 4 groups including normal temperature control (NTC) group, normal temperature cooling therapy (NCT) group, hot and humid control (HHC) group and hot and humid cooling therapy (HCT) group. Different interventions were applied as indicated in the rats with superficial second-degree scald burn, with the dry bulb temperature(Tdb) at 26.33±1.29 ℃ and relative humidity (rh) of 71.05%±4.57 % for two normal temperature groups, and Tdb at 35.33±0.35 ℃ and rh of 70.81%±1.38% for the two hot and humid groups. The exposure time was 120 min in NCT and HCT groups, and the HR and MAP were measured every 20 min. Results MAP is not influenced by environmental temperature and the cooling therapy (P>0.05), whereas HR was higher in HHC than in NTC group and also in HCT than in NCT group (P=0.003), lower in HCT and NCT groups than in HHC and NTC groups (P=0.002), respectively. HR did not undergo any significant changes during the observation in the 4 groups (P>0.05). HR was higher in HHC and HCT than in NTC and NCT groups at 65, 85, 105 and 125 min after the burns, but compared with the two control groups, cooling therapy decreased HR at 5, 25, 45 and 85 min. Conclusion Cooling therapy does not affect MAP but efficiently decreases HR, which may prevent further heat injury.