In order to investigate the ability of body temperature regulation and thermoregulation in Apodemus chevrieri, body temperature and rest metabolic rate (RMR) were measured during postnatal development (1～42 day). The result showed that body temperature and RMR of pups in A. chevrieri increased according to the increase of ambient temperature during on day 1 and 7, body temperature of pups were lower in low temperature and RMR increased significantly when on day 14, RMR of pups was extreme significantly higher in low temperature than that in other temperature when on day 21, RMR of pups increased in high temperature(35℃) on day 28, and the thermal neutral zone were 22.5 to 30℃ on day 35 and 42, which approached its adult level. All of these results indicated that pups of A. chevrieri in the different growing period had different thermogenesis and energy allocation to maintain stable to body temperature, thermogenesis was weaker in the early phase of postnatal development, most of energy is used to its growth. After pups were weaned, the ability of constant temperature and thermoregulation developed quickly to adjust variations of environment during postnatal development.