Background: The traditional healthcare process centers on the hospital rather than the individual patient. The demand for continuous monitoring is increasing with the increasing proportion of patients with chronic diseases and the elderly. Wearable medical devices have brought medical monitoring into the Internet age. To improve the devices' adaptability, this research proposes a combination between digital twin (DT) and wearable medical devices is proposed to provide personalized wearable medical devices and personalized healthcare efficiently. Methods: A DT-enabled smart system is proposed for personalization in the design, manufacturing, and data tracking of a healthcare device prototype. A case study is made for three healthcare monitoring scenarios: rehabilitation training, wheelchair, and human fall. Based on computer-aided design and additive print, a triaxial vibration collection bracelet with a simple Internet of things mode is designed and manufactured in personalization. Results: The bracelet shows great application ability in this case study, including design, manufacturing, and remote connection. 10 groups of data were recorded in each scenario. In rehabilitation training and wheelchair experiments, the average values of correlation coefficient between models and the actual data are 0.991 and 0.749 respectively. In human fall experiment, the motion signal parameters of the user and movement pattern were clearly identified. These results provide the basis for applications in different scenarios. Conclusions: The device is representative, with good personalization and health monitoring performance, and has excellent potential for large-scale application. DT will provide a new feasible solution for the realization of personalized medicine.