Abstract: Objective:To investigate changes of thermoregulatory responses and hsp70in 10-day heat acclimation of middle-long-distance runners, and explore how to establish heat acclimation in practice of training and competing.Methods:Taking 8 middle-long-distance runners as the research objects.In a hot environment (33℃, 80% relative humidity) , participants were asked to cycle at 40% of their VO2 max workload for 60minutes during 10days, and the indexes of thermoregulatory responses were measures on 2, 6, 10days.Results:There were some regular and adaptable changes of body core temperature, heat rate, ratings of perceived exertion, sweat loss, sweat rate and sweat ion of middle-long-distance runners in 10-day heat acclimation.The body core temperature, heat rate and sweat ion were decreased.The sweat rate was increased.The serum concentration of hsp70 was increased.Conclusion:The adaptable changes of body core temperature, heat rate, sweating, hsp70in 10-day heat acclimation suggested that the heat acclimation of middle-long-distance runners were successfully came into being.