In order to explain the daily cyclic variation of metabolism and thermoregulation in the Silky Starling (Sturnus sericeus), the 24 hours continuous changes of body temperature (T_b), body mass (M_b) and basal metabolic rate (BMR) in silky starling were measured. T_b was determined by a digital thermometer (Beijing Normal University Instruments Co., model TH-212) inserting to cloaca, M_b was measured by an electronic scale (Mettler-Toledo, model PL3001-S) to the nearest 0.1 g, and BMR was measured by an open oxygen analyzer (AEI, model S-3A/I) temperature controlled at 25±0.5℃, respectively. The results showed that daily variation of T_b, M_b and BMR was great significantly. Both of T_b and M_b were significantly lower and varied greatly in night time than those in day time. The lowest T_b was 40.4±0.1℃ at 5 o’clock. The value of M_b showed a obvious linear variation with time during 20:00-6:00, and the relationship of M_b in female was M_b=83.46 (±0.12)-0.41 (±0.02) t (R²=0.992, P<0.01) and in male was M_b=76.74 (±0.15)-0.39 (±0.02) t (R²=0.986, P<0.01), respectively. The lowest BMR was (1.96±0.06) ml/(g·h) at 4 o’clock. In summary, silky starling could adjust their daily cyclic variation by decrease T_b, M_b and BMR at night. This inner physiological energetic regulation mechanism improved their acclimatization to the diurnal environment variation.