To compare daily rhythms of Eothenomys miletus and Apodemus chevrieri which sympatric distributed in Hengduan Mountains region,their thermoregulation and evaporative water loss (EWL) were measured four times in 04:00-06:00,10:00-12:00,16:00-18:00,and 22:00-24:00 within 24 hours from 24 adult samples (12♀ and 12 ♂ ) for each species.E.miletus and A.chevrieri had a similar body temperature (T_b) circadian rhythm,their maximum body temperature,37.45±0.17℃ and 37.30±0.24℃,occurred at 04:00-06:00,respectively,and their minimum body temperature,35.77±0.42℃ and 36.05±0.11℃,occurred at 10:00-12:00.However,significant differences between the two species were found in nonshivering thermogenesis (NST),basal metabolic rate (BMR),thermal conductance (C) and dry thermal conductance (Cdry).EWL appeared a significant difference only at 16:00-18:00.E.miletus had clear circadian rhythms in BMR and EWL.The NST circadian variation in A.chevrieri corresponded to the T_b oscillations,moreover the daily rhythms of C and Cdry were also synchronous with ambient temperature.Suffering high temperature and low temperature,the two species adapt to environmental conditions by taking the similar daily rhythms of T_b.Compared to E.miletus, A.chevrieri has a stronger physiological regulation mechanism to maintain water and energy balance.