The fashion industry is one of the growing and popular industries in the world, but at the same time, it is a transient and constantly changing phenomenon. The current research on the topic of designing a model of brand equity in fast fashion clothing is based on the data theory of the foundation. This research is of a qualitative type and with an inductive approach, which has designed the model using the research strategy of the Foundation's data theory and the systematic design of Strauss and Corbin. The statistical population of this research consists of 16 managers of Iranian clothing brands as well as marketing and branding professors, whose selection was based on the snowball method. Data collection was done by in-depth interview and analysis of interview data was done based on open, central and selective coding. The findings from the data are summarized in the three dimensions of conditions, interactions and consequences. Market research, brand identity and personality are causal conditions, and brand awareness, positive image of the brand and perceived value play the central role of the phenomenon. Internal branding, public relations and advertising, along with marketing strategies as strategies, play the role of facilitating the realization of phenomena into outcomes. Economic factors, legal factors, foreign competitors and influential groups also play an intervening role. Infrastructures and culture constitute the land factors that exist in the context of the discussion.