The World Wide Web is increasingly being used as a vehicle for flexible learning, where learning is seen to be free from time, geographical, and participation constraints. In addition to flexibility, the Web facilitates student-centered approaches, creating a motivating and active learning environment. The purpose of this study is to set up an adaptive learning environment on Internet and to experiment with the most suitable methods and applications. Our goal is to provide a better solution with regard to the related distance learning research. All the resources and background are from current relevant documents on the theory of asynchronous distance education. We set up an adaptive Internet learning system based on learning theory and related learning models. Our research targets are those students who took the "Life Chemistry" course for the asynchronous distance education environment at Providence University at Taiwan. The students were divided randomly into two groups: the experimental group, which was in an adaptive learning environment and the controlled group, which was in a non-adaptive one. We used the American Chemistry Society Test Bank as our research tool and used SPSS to analyse the data we obtained. Results show that the experimental group in the adaptive learning environment out-performs the controlled group. In addition, those students who are field independent learning types, have higher pre-knowledge, are male, in science departments and have a longer study time span in an adaptive learning environment show much greater achievement levels than those in the opposite situations.