The purpose of this study is to investigate the relationship among excessive service, customer emotion and satisfaction as well as the mediating effect of difficult customer. 412 data has been collected by survey questionnaire on sites of Wang Steak restaurant around Taiwan. Regression analysis and hierarchical regression analysis have been applied to analyze the influences and mediating effects among variables. Results shown that excessive service has significant influence on positive emotion; but hasn't significant influence on customer satisfaction. In addition, positive emotion has significant moderating effect between excessive service and customer satisfaction. However, difficult customer has no significant effect between excessive service and customer emotion.