The aim of this study is to investigate the factors that affect students' participation in the online learning environment (OLE) for distance learning students of mathematics at the Open Learning University of Hong Kong (OUHK) and to find out the suggestions that can improve students' use of the OLE. A questionnaire was designed to survey to students' usage pattern of OLE (called WebCT). The analysis of the results obtained from the open-ended questions in the questionnaire and the interviews revealed that students liked using the OLE for sharing and learning from each other. They also preferred to have tutorial notes and the solutions of the assignments. To improve WebCT, students suggested adding electronic submission for assignments, students' assignment records, Chinese characters and a mathematical science package.