At present, there are various courses and complicated course relationship in universities, which is not good for students to make rational course arrangement. To address this, Course Relationship Network System (CRNS) is implemented. It proposes a marked traversal algorithm based on depth-first approach which helps to show the relationship between courses with a multilevel graph. Besides, all reasonable learning paths can be analyzed and obtained under different strategies. The system is based on Rich Internet Application (RIA) that can provide students rich learning experience. The result indicates that students can acquire graphical course relationship information and learning paths rapidly and accurately. In this paper, the algorithm of generating Course Relationship Network (CRN), database design, system architecture and key techniques are introduced. Now, CRNS is running in Capital Normal University.