In the information-oriented society, the paradigm of education has changed from the existing traditional teaching-centered education to the learning-centered education. In the Web-based Learning System which an learning-centered educational environment using the internet, students should have responsibility of their learning as taking more opportunities to participate their learning positively, to control their process of learning and to evaluate their learning by themselves to improve self-directed loaming ability. In this paper, the Web-based Learning System with a Self-Study Plan to lead students to select own purposes and methods of the study and write a self_evaluation is developed. The Self-Study Plan is a guide to lead the process, an order to have an individualized study and a report to evaluate own study. In addition, the suggested System is designed through object-oriented method using the extension mechanism of UML to archive the improvement of reuse and maintenance.