Web 2.0 communities are providing new opportunities for teachers’ professional development by supporting more flexible sharing, communicating, and collaborating among teachers at a distance. Meanwhile, literature concerning teachers’ professional development increasingly places value on communities of practice and web-based learning communities. This paper presents a case study on the design of teacher training supported by a Web 2.0 community. The training program discussed in the paper is characterized by employing peer-coaching to facilitate teachers’ learning in a Web 2.0 community, and is a part of a project funded by the Ford Foundation. The paper gives a brief introduction to the training program, and reports some important findings and reflections on design and practice for in-service teacher training. It includes the theoretical framework design, a training model as well as activity design, and the implementation and evaluation of the training program and useful experiences. Initially, taking account school teachers’ needs at the K12 level for curriculum reform and quality education, theory, knowledge and practice competences for learner-centered instruction were examined by using peer-coaching methods supported by online communities. The suggested training program was delivered in two Chinese districts in August 2009: Tianhe district of Guangzhou, and Wuhou district of Chengdu. More than 120 participants, including subject teachers, school principals and local teaching researchers, took part in the f2f training, online activities and the further practice activities. Even still on-going, the comprehensive investigation and evaluation of the training program explains that the initial results and observations collected during the process of training are very positive. With cause for optimism as to the prospect of achieving the training program’s goals, the study has demonstrated that a task-driven approach and peer-coaching supported by a web 2.0 community are effective methods for in-service teacher training, and that peer-coaching can be greatly extended by out-of-school activities.