The present invention relates to a mounting structure of a curtain airbag for a vehicle. An airbag cushion which is deployed by deploying pressure of an inflator is mounted between an inner side panel so as to stably deploy toward a cabin through a portion where a head lining and a pillar trim are matched. The inflator is installed between the inner side panel and an outer side panel, and the airbag cushion is installed between the head lining and the inner side panel.