Knowledge-sharing and resource exchange are the key to the success of collaborative design learning. In an architectural design studio, design knowledge entails learning efforts that need to accumulate and recombine dispersed and complementary pieces of knowledge. In this research, firstly, "Knowledge Trading Game" is proposed to be a way for promoting students' design knowledge exchange, dissemination and refinement. Twelve students are randomly chosen as experimental participants. And secondly, "virtual value" is used for students to trade their design knowledge. In this game, students buy others' design knowledge to extend their design problem space; students decrease their design solution space through their sold design knowledge. Finally, "protocol analysis" is adapted as the research methodology to examine the results of implementation. A positive outcome is identified that Knowledge Trading Game encourages collaborative design learning.