Background <p>Researchers have long examined the relationship between media use and negative psychological states. However, the correlation between hopelessness, parasocial relationships, and self-identity/ well-being on short-form video platforms is unknown. Additionally, the perceived similarity’s role in moderating these relationships has not been established.</p> Methods <p>Drawing on the theoretical model for the development of parasocial relationships, we tested and confirmed the validity of a moderated mediation model, demonstrating how individuals experiencing hopelessness may obtain self-identity and well-being via the mediation of parasocial relationships and the moderation of perceived similarities on short-form video platforms.</p> Results <p>The results of a survey among 2,902 users of short-form video platforms in China indicated that parasocial relationships mediated the relationship between hopelessness and self-identity/well-being. Perceived similarities had a significant moderation effect on the relationship between hopelessness and PSR and the indirect effect of perceived similarities on self-identity (or well-being).</p> Conclusion <p>Users on short-form video platforms can autonomously derive positive health effects (self-identity/well-being) via PSRs. Perceived similarity exerted a moderating effect on the relationship between hopelessness and PSRs among individuals on short-form video platforms: the positive relationship between hopelessness and PSR is stronger for individuals with higher perceived similarities.</p>