The purpose of this master’s report was to investigate how Chinese students who were learning English used Web 2.0 tools for informal learning and to construct a model of informal learning in the Web 2.0 environment. I conducted a pilot study with 32 Chinese students who were learning English and tried to understand how they used Web 2.0 tools as informal learning tools to improve their English. Furthermore, I discussed the main challenges of informal learning in a Web 2.0 environment from the learners’ perspective and from a technical perspective. Then I proposed a model of informal learning in a Web 2.0 environment which may improve learning in an informal learning environment, and provide learners a possible learning method. It is hoped that this model will help students better master learning methods of informal learning in the Web 2.0 environment and lay a good foundation for lifelong learning. / text