PurposeThe purpose of this paper is to identify the dimensions and formation mechanisms of brand value on social media platforms within the prosumption logic based on the theory of value co-creation. By adopting a process-oriented mindset, this study deconstructs and applies the prosumption theory and the theory of value co-creation in the field of social media, thereby addressing the insufficiencies of previous research that focused primarily on the subject mindset. It offers reference ideas for social media brand managers to attract prosumers to engage in value co-creation.Design/methodology/approachThe crawler technology and grounded theoretical method were adopted in this research paper.FindingsBased on the logic of prosumption and the theory of value co-creation, the research finds that the brand value of social media platforms is composed of seven dimensions. The dimensions include brand recognition, brand perception quality, brand experience, brand value-in-use, brand relationship quality, brand loyalty and brand co-creation behavior. From the perspective of prosumption logic, the formation of brand value on social media platforms is a gradual accumulation process. This process involves prosumers participating in prosumption activities, progressing through several stages. Initially, it starts with “prosumption conditions”, which include brand recognition, brand perception quality and brand experience. It then moves to “prosumption processes,” characterized by brand value-in-use and brand relationship quality. Finally, it culminates in “prosumption outcomes,” represented by brand loyalty and brand co-creation behavior. From the perspective of value creation, the formation of brand value on social media platforms is a closed-loop process that includes “brand value identification and empowerment—brand value acquisition and transformation—brand value co-creation and relationship upgradation—brand value co-creation and stability—brand value feedback and iteration.”Originality/valueThe findings contribute to expanding prosumption and co-creation theory and enriching the prosumption logic frame. Meanwhile, it is conducive to encouraging prosumers to participate in the platform’s prosumption activities and jointly creating the brand value of the social media platform. This paper interprets prosumption through the lens of the value co-creation process.