In this research, a conceptual model of a wiki-based collaborative process writing pedagogy (WCPWP) is developed using a design-based research (DBR) methodology. The intention is to help the teaching and learning of Chinese writing among mainland Chinese upper primary school students. The wiki-based learning environment Joyous Writing Club (JWC) (www.joyouswriting.com) was designed and developed. The study was conducted in a primary school in Shenzhen, China, and divided into three iterative research phases spanning one and a half years (three semesters). Over this time the WCPWP was developed and refined. In this study, both quantitative and qualitative methods, including online wiki documents, a course feedback questionnaire, observations, interviews, and a teacher's questionnaire, were used to collect data. The results indicated that the Chinese language teachers and most of the students had positive attitudes and perceptions toward WCPWP. They perceived that the WCPWP had positive effects on students' writing ability, writing attitudes, collaboration, reading, and oral expression. This study illustrates in detail the process of improving the WCPWP, and is a good example of how DBR can be used to design and develop pedagogy. The resulting development of a conceptual model of a high-grade WCPWP may help primary school teachers enrich the pedagogical knowledge related to wikis and Chinese writing.