The fluctuations of petroleum price influence the global economical development, and therefore our government publicizes the importance of energy efficiency and carbon reduction strongly. People can understand the effect analysis of project-based learning for the whole learning of third grade students in elementary school with the methods of observation and interview in teaching activities. The major purposes are to discuss as follows: 1. The cognition change of simple solar vehicles' production for students 2. The history and effects for learning about energy efficiency and carbon reduction by project-based learning 3. The attitude shift for energy efficiency and carbon reduction in their life It emphasizes the method discussion and problem solution to strengthen the ability of technological development and cultivate the lifetime self-study. Besides, students can understand the categories and effects of energy resources and solar vehicle's production initially. They can also apply the new idea of energy efficiency and carbon reduction in their life.