Through the literature review and elementary school teacher interview, we found that most of students prepared their assessments of the unit of plants by recitation. Although there are several researchers designed digital assistant instructional materials to aid students for plant-unit learning, helping student learning effectively is still a critical issue. Based on this point, the purpose of this study was to design a learning game for students in Facebook, and use the quasi-experimental research method to explore the learning effects between experimental group (Facebook game learning) and control group (pen and paper learning) in fifth-grade elementary school students. By ANCOVA analysis, we found that the learning effect of the experimental group students in plant-unit learning assessment are significantly better than that of control group students. The satisfaction mean score of Facebook game learning is 4.32 (Likert Five-Point Scale) in experimental group, and the analysis of interview data shows that students are interesting in Facebook games learning, the learning motivation and confidence were promoted in cooperative learning groups. According these findings, this study summarized four conclusions and four recommendations as a reference for follow-up study.