Objective To observe the changes of circadian characteristics and stress-response-related physiological parameters including respiration, blood pressure, electrocardiography and body temperature of conscious rhesus monkeys by implantable telemetry technique. Methods Surgery was performed on 8 rhesus monkeys (half male and half female, 3-5 years old) for implantation of a telemetry transmitter. After 3 weeks of recovery, the physiological parameters of respiration, blood pressure, electrocardiography and body temperature of the conscious rhesus monkeys without binding were automatically recorded by a DSI telemetry system and the data were analyzed by the Ponemah software. Results Some electrocardiographic indexes showed significant differences at daytime and nighttime (P＜ 0. 05 or P＜ 0. 01) including mean heart rate (HR) ( 155. 0-122. 4 times/min), respiratory rate interval (RR-I) (410. 8-535. 7 ms), T-wave amplitude (T-A) (0. 181-0. 157 mV), PR interval (PR-I) (80. 4-87. 4 ms), QT interval (QT-I) (224. 8-263. 9 ms), and corrected QTcb interval (QTcb) (352. 3-366. 7 ms). The indexes of blood pressure and respiration at daytime were significantly higher than those at nighttime (P＜ 0. 01), including the mean systolic pressure (SYS) at daytime and nighttime (144. 6-131. 6 mmHg), diastolic pressure (DIA) (99. 8- 89. 9 mmHg), mean arterial pressure (MAP) (121. 5-110. 2 mmHg), tidal volume (TV) (64. 5-36. 6 mL), minute ventilation (MV) (1931. 9-920. 1 mL/min), and respiratory rate (RR) (32. 3-25. 4 times/min). Cleaning and feeding activities of the laboratory staff at 9: 00 a.m. and 2: 00 p.m. had a certain effect on the stress-responses in the monkeys. Conclusions The parameters of respiration, blood pressure, electrocardiography and body temperature of the conscious rhesus macaques observed by implanted telemetry system show obvious circadian changes, which can truly reflect the changes of physiological indexes at daytime and nighttime, and avoid the stress in hungry monkeys caused by the feeding and cleaning activities of laboratory staff. This technique can improve the efficiency of drug safety pharmacology studies, reduce the number of animals used and meet the requirements of 3R principles.