This study tried to analyzed the relationship between core competence, satisfaction, trust and loyalty in order to suggest to a methodology for decision-making of e-trade firms. 6 hypothesis were constructed for analysis based on previous literature review. The results of empirical analysis shows that core competence gave significant effect on satisfaction, trust and loyalty, and satisfaction gave positively effect to trust and loyalty. Besides trust affected positively on loyalty. These result explains that e-trade firms which try to create customers must build high level of core competence should be realized and reacted for maintenance of created customers.