Good learning motivation plays an important role in defining learning objectives, straightening learning attitudes, and stimulating learning potentials. Existing strategies of strengthening the learning motivation of students are promoting peer interaction, introducing game-based teaching activities, or simply combining the before-mentioned two strategies, and they all have their limitations. In view of this, in this paper, a novel game based peer learning strategy is designed by comprehensively considering both the competition mode and the cooperation mode in peer interaction and employing a rich game mechanism. Then, a game based peer learning system is developed on the basis of our proposed strategy. The proposed system can create a game based online collaborative question-answering environment for students. In this environment, the system assigns students to different levels according to their historical question-answering records so that students can freely team up according to the hierarchical income rules and answer questions cooperatively. Finally, on the basis of the grade levels and question-answering results of the team members, the system calculates their question-answering incomes and updates their grade levels accordingly. Teaching practices show that the proposed game based peer learning system enhances the learning motivation of students.