Using digital learning content to realize learning in games is a rapidly-developing direction of interest for teachers and researchers. This study has developed a digital role-playing gaming system to review Social Studies course content to a fifth Grade class at an elementary school. It allows students to experience the historical storyline of Tamsui, located in the north of Taiwan, by playing the role of Dr. Mackay. An experiment was conducted to evaluate the potential effects of the proposed system when applied to the reviewing activity of Humanities courses. The results of the post-test scores showed that the proposed system is not superior to the traditional teaching method which uses PowerPoint-based slides with the teacher's oral instruction, but it still enhances their overall learning performance after the reviewing activity. Moreover, the results of the questionnaire survey showed that the students who reviewed by using the proposed system showed a higher learning motivation than those reviewing with the traditional teaching method. It is therefore concluded that our role-playing digital gaming system can be used to assist the teachers' teaching activities, because it allows the students to complete their reviewing activity by themselves, and it effectively enhances their learning performances and motivation.