Self-directed learning has been researched by scholars for many years. However, there is a lack of literature on web-based self-directed Mandarin learning. This research was aimed to investigate how students can learn Mandarin through self-directed study with Internet resources, what the advantages and challenges are, and what strategies students could use to enhance their self-directed Mandarin learning. A web-based survey and indepth interviews were conducted with students at West Liberty University (WLU), West Liberty, West Virginia, U.S.A. The research found that most of the subjects chose to learn Mandarin because of personal interest, most of the subjects have difficulty in finding appropriate Internet resources although they have been using various types of Internet resources to learn Mandarin, and the biggest challenge they have encountered is that the lack of face-to-face interaction inhibits their learning. This research also put forward some strategies to enhance web-based self-directed Mandarin learning and some recommendations for future research.