In this paper, a practical e-learning system, called project experience center (PEC), for an ”object-oriented system analysis and design” course is proposed. The goal of this system is to provide not only theories but also practical examples such that students can understand Unified Modeling Language (UML) easily. For this purpose, a project model and experience metadata set are designed to store the ”experiences” of students who have previously taken the same course. These ”experiences” could be diagrams drawn by using UML, documents for these diagrams, and program source codes. New learners who are not familiar with the UML diagrams could retrieve experiences from this system. They can use similar examples as references and practice their own works. We believe this process can expedite the UML learners to understand when and how to use the UML notations properly. This system was used and evaluated in a University in Taiwan. The results show that students were satisfied with the system's supports and found it is easier to use this system than to find examples from books or other resources.