Service quality represents the external image of an organization. The aim of this study is to help enterprises understand the factors influencing service quality and gain improvements in the aspect of theory and practice. A questionnaire was distributed to 247 frontline employees in 3 call centers to study the impact of job demands and customer mistreatment on customer-oriented organizational citizenship behavior. This study is based on the affective events theory, and used burnout to play a mediating role. The results were as follows : (1) Job demands and customer mistreatment have a positive effect on burnout, (2) Burnout has a negative effect on customer-oriented organizational citizenship behavior, (3) Burnout partly mediated the relationship between job demands and customer-oriented organizational citizenship behavior, as well as between customer mistreatment and customer-oriented organizational citizenship behavior.