This study, based on social impact and regulatory mode theories, investigates the mechanisms of engagement intention through scenario experiments. The results indicate that: (1) there exists an inverted U-shaped relationship between travel influencers' follower size and consumers' predictive expectations, as well as engagement intention; (2) predictive expectations serve as an instantaneous mediator; (3) compared to the locomotion-mode consumers, assessment-mode consumers enhance the inverted U-shaped relationship as described above. This study offers a novel theoretical perspective on marketing undertaken by travel influencers and provides specific recommendations which tourism companies can use in relation to influencer marketing.