Purpose: This study extends the commitment-trust theory from the perspective of relationship marketing and explores its effect on purchase intention under the moderation of trust by investigating vloggers' relationship marketing in the context of social media. Design/methodology/approach: The study employs a survey investigation with online questionnaires in China, and the hypotheses were tested using multiple regression analyses, with 319 valid consumer responses. Findings: The findings reveal that the extended commitment-trust theory is applicable in the context of social media. Perceived relationship commitment, expertise, physical attractiveness, social attractiveness and self-disclosure play a significant role in predicting purchase intention. Relationship commitment proves to be a mediator between the antecedents and purchase intention. Trust shows a moderating effect on the antecedents and relationship commitment. Originality/value: The study provides evidence of the importance of the above-mentioned antecedents in influencing viewers' relationship commitment to vloggers in the context of social media. The results contribute to the development of the commitment-trust theory and an understanding of the theory's underlying mechanisms. The result also provides further evidence of the effect of trust on relationship commitment.