169 eligible participants aged between 60 and 80 were enrolled in an intervention program focusing on exercising Ba Duan Jin (BDJ), a traditional Chinese health exercise, to improve the balance ability, which was launched in three communities in Shanghai from 2016 to 2017 with an average length of 6 months. One of attractive innovations in this program is that a nine-axis inertial system based bracelet has been particularly developed and adopted to record BDJ exercise situation. Routinely paper-based log was also required to record the exercise. The group interview targeting on the feeling of using the bracelet and the comparison of electronic and self-reported records were conducted to evaluate the effect of the bracelet in promoting this intervention program which were summarized as below: 1. The bracelet could enhance participants’ enthusiasm and the sense of acquisition through the utilization of the characteristic curve. This curve contains eight unique waveforms which could be exactly mapped to each movement in BDJ. So, two questions that participants usually concerned, ‘how could I improve exercise’ and ‘whether my exercise has been improved’, could be addressed through comparing the current shape of the curve with a standard one performed by a professional instructor and using the previous shape as a benchmark to track the trajectory of exercise proficiency. 2. The bracelet could generate a high-quality data record which is very crucial for the impact evaluation of an intervention. The time, duration, frequency of BDJ exercise could be precisely and real-time recorded by the bracelet with minimal burden and no recall bias. 3. The bracelet could make the ‘Big data’ and ‘Precise intervention’ applicable in such a community-based program. With the integration of other biosensors, more physiological indicators, such as blood pressure, heart rate and sleep quality could be easily recorded simultaneously.