Introduction: Insufficient physical activity of elementary school students have resulted in the increase of the obesity rate year by year, further causing healthy threat, the reduce of physical fitness, and cardiovascular and chronic diseases after adult. In this study, we first explored the effects of wearable fitness watch on the body mass index and physical fitness performance of elementary school students, and further used the wearable fitness watch stage strategy to monitor the physical activity promoted situation of township and metropolitan areas schoolchildren. Methods: The subjects were divided into two groups, the experimental group, including township and metropolitan areas schoolchildren in four classes (n=88) and the general group, including metropolitan areas schoolchildren in three classes (n=83). The schoolchildren are all voluntary participants. The subjects conducted physical fitness tests and BMI measurements, before and after the experimental intervention, respectively. The t test was used to examine the significant effects of two groups before and after the experiment. In the experimental group, the 12-week four-stage wearable fitness watch strategy intervention was conducted to observe physical activity intensity and time changes. In physical activity, the mixed-design of two-way analysis of variance ANOVA is adopted to analyze the parameters such as the average daily number of steps, moderate to vigorous physical activity (MVPA) accumulation time and movement step frequency…etc. at two regions in four stages. Results: In the standing long jump project, the physical activity increase on post-test results in the experimental group was obviously greater than that in the general group (t=5.32, p < .05); also, the 12-week wearable fitness watch strategy enhanced the results of sit-ups and 800-meter running performance. Thus, it could improve body mass index. Nevertheless, there was no statistically significant difference in the item of sit and reach (p > .05). In the experimental group, the 12-week wearable fitness watch strategy could not only effectively promote the physical activity intensity of elementary school students to increase with the stage strategy, achieving significant differences (F=13.862, p < .05), but also significantly improved daily walking steps and MVPA accumulation time. Conclusion: Wearable fitness watch can help to promote physical fitness performance and improving undesirable BMI conditions. Through the wearable fitness watch strategy intervention accurately understand and effectively enhance the intensity of physical activity of township and metropolitan areas schoolchildren. Consequently, wearable fitness watch is worth to be promoted as the tool of enhancing personal physical activity.