Objective: To assess the effects of a closed-loop implanted chip system on heart rate regulation in conscious rabbits. Methods: Twelve rabbits with normal heart rate (HR) were randomly divided into the control and the vagus nerve stimulation (VNS) groups. In the VNS group, all the animals were implanted the self-developed closed-loop chip for a week. The right vagus nerve of rabbit was randomly stimulated by the chip according to real-time feedback of HR at different times. Each rabbit underwent 1 hour of regulation and 1 hour of recovery. The control group was implanted the chip without any stimulation. MD2000WL software recorded the real-time electrocardiogram (ECG). HR was calculated by the chip according to the ECG. Results: The implanted closed-loop chip system worked well in conscious rabbits in vivo. The chip recorded complete ECG. There was a significant decrease of HR during the regulation [(265.2 ± 15.2) bpm vs. (289.5 ± 15.7) bpm, P < 0.05] compared with the baseline HR in the VNS group. The HR was also significantly decreased during regulation in the VNS group [(-24.3 ± 3.6) bpm vs. (-4.6 ± 5.1) bpm, P < 0.05] compared with the control group. Conclusion: The implanted closed-loop chip system can successfully regulate the heart rate of conscious rabbits in long term.