Based on the perspectives of job demands-resources model, we explore how and when service provider's emotional demands impair service performance; specifically, we predict that emotional demands negatively affects service performance via the mediator of job burnout (health impairment process), and that this mediating process is moderated by service provider's occupational identity. Using questionnaire survey, we collected supervisor-subordinate (service provider) dyad data and obtained 211 valid pairs of data. Results showed that emotional demands impair service performance via the mediator of job burnout. Occupational identity weakens this mediating process. We discussed the theoretical and practical implications as well as limitations and future research directions at the end.