Background: Previous studies have reported that an increased amount of physical activity (PA) can reduce obesity and hence decrease the risk of chronic diseases. However, few numbers of researches used accelerometers to investigate the association between free-living PA and health promotion. In this study, accelerometers were used to investigate how a 6-week lifestyle intervention affects PA and body composition in overweight women. Methods: Fifteen overweight women (mean age: 46.1 ± 10.3 years) in the community participated in the study. The lifestyle intervention consisted of nutrition education and complex PA training. Accelerometers and body composition analyzers were used to assess the PA and body composition in the preparatory week, and a week after intervention. Results: After the lifestyle intervention, the mean steps/day and time spent in moderate-to-vigorous intensity PA were increased significantly (p<0.05).The BMI, percentage of fat and fat mass of participants on the other hand were decreased significantly (p<0.05). However, there was no significant difference in muscle mass before and after the intervention (p>0.05). Conclusions: The 6-week lifestyle intervention program is a viable starting point for overweight women to initialize their daily PA. The complex physical activity contributes 50% of weight reducing in community overweight women after 6-week lifestyle intervention. It helps the change of body composition.