The purpose of this study is to use fuzzy theory to evaluate web-based learning. In this study, integrating an on-line test, individual homework and cooperation learning scores precedes comprehensive evaluation for learners on web-based courses. Based on web environment, an on-line testing system is also given to evaluate whether learners finish what they have learned. The feedbacks relating information from evaluation system can provide the learners to facilitate their self-estimation, so that learners are able to modify their own learning strategies to improve their learning efficiency.