As one of the leading serious public health problems globally, physical inactivity is considered to be related to many diseases. During the transition period into adults, adolescents' physical activity (PA) level decreases sharply. Meanwhile, the wide use of social media among young people provides inspiration for researchers to conduct online social media-based interventions to increase their PA. Online social networks such as Facebook are usually popular, easy to access, and cost-effective; can be used to assist the formation of social groups; and can be translated into health promotion practice relatively easily, which may help a lot to solve the problems of PA participation and adherence. However, it is still unclear how effective and successful the features of online social media will be during an intervention. The objective of this paper is to identify the effectiveness and successful features of Facebook in adolescents by reviewing relevant studies and to examine how Facebook works to influence PA. Keywords including 'Facebook OR social network OR social media OR Twitter OR LinkedIn OR web OR internet' combined with 'physical activity OR physical fitness' were used to search in PubMed from 2005 to 2016, and in total, 136 results were collected. Among them, 20 met the criteria. Most studies showed an increase in self-reported PA overtime, which demonstrated the effectiveness of online social networks, while the lack of a true control group limited the ability to assess the effect of Facebook separately. Social support, team formation, motivation, goal-setting, tailored feedback, appropriate competition, and preferable design were successful features. Considering the different focus of adolescents and guiding in accordance with aptitude may improve effectiveness. In this research field, still in its infancy, the applicability of these features to Hong Kong adolescents via online social media (i.e., Facebook or WeChat) PA intervention remains to be determined in future studies.