This study examines the effectiveness of an approach for improving Chinese as a foreign language learners’ language proficiency, especially their speaking ability. Built upon the Educational Engineering Research Theory and its Distributed Design Model, this study used a wiki-enhanced Task-Based Language Teaching (TBLT) approach implemented at the syllabus level, taking into consideration various learning contexts. Different aspects of the design, such as how the wiki was used to extend the students’ learning beyond classroom, how the topics of the tasks were chosen and sequenced, and what strategies were adopted to motivate learners to interact with their co-learners and native speakers are discussed to provide insights on the use of TBLT in a more detailed way for practitioners. Findings show that the implementation of the TBLT syllabus with the support of the wiki significantly improved learners’ language proficiency as well as the fluency, accuracy, and speed of their story narration and the fluency of their problem-solving conversation.