The purpose of this research is to apply the two-sided market theory which is being studied recently in economics to service industries. In two-sided platform businesses two distinctive customers group interact each other through a certain platform provided by a mediator affected by indirect network externality. They provide these customers a real or virtual meeting place, and they facilitate the interactions between members of these customer groups. They essentially act a intermediaries between the two groups and create efficiencies by lowing transactions costs and reducing duplication costs. Many significant industries are populated by business based on two-sided market especially in service industries. These included many traditional businesses, such as shopping malls, and most Internet-based businesses, such as social networks. With characteristics of platform and indirect network externality, competitive factors of two-sided platform businesses in service industry markets can be re-explained differently from the previous theories for one-sided markets. To find and classify these factors, this research proposal goes over previous researches about the two-sided market, and researches several cases in service industries as case study analysis. Therefore, to find out factors strengthened competitive advantage for service industries is available.