Different genres of underground music are important issues in Iranian youth culture. The purpose of this research was to study masculinity in Iranian- Persian rap music. Therefore, Persian rap music as a part of Iranian popular culture, between 2001 and 2011 was analyzed. We used qualitative research approach. The main method used in this study, was "Constructive Grounded Theory ". So instead of using existing theories as a theoretical framework, the researcher sought to generate local theory from research field. Thus, using theoretical sampling, data compiled from various sources. The multiple data collection techniques such as interviews, observation, online observation, collecting documents and texts were used. Then all the data was coded with using open, axial and selective coding methods. Finally, 62 concepts and 16 categories derived from data and "plural form of masculinity in Iranian-Persian rap music" was defined as the core category. Then according to paradigmatic model, "Substantive Theory" emerged from the data, was presented as "story" and "visual model". Finally seven questions of Strauss and Corbin about the experience in research has been assessed to evaluating research.