From individual difference perspective, the present study aimed to explore the effect of neuroticism on users' willingness to pay for online knowledge, and the underlying mechanism as well. An online survey was used for data collection, and the bootstrapping strategy was adopted to test the proposed moderated mediation model. As the results show, among users with high epistemic curiosity, social comparison fully mediates neuroticism and willingness to pay; whereas among those with low epistemic curiosity, neuroticism directly influence user willingness to pay without any mediating effect of social comparison.