This study focuses on the internal conditions of students' concept learning and builds a learning cycle' based on the "phases of the Moon" (MP) to, deepen students' understanding. The learning cycle of MP developed in this study includes three basic learning links, which are: cognitive conflict, abstraction and generalization, and transfer practices. The three basic learning links are named CAT for short. A teaching courseware based on CAT for MP is developed and tested in real classes. 667 students and 21 science teachers use this courseware in 9 primary schools in Beijing. Three approaches for collecting data are incorporated, including: questionnaire surveys for students, interviews for students and teachers, as well as classroom observations by teachers. Findings indicate that CAT for MP is useful to engage students' thinking and deepen students' understanding of MP. Findings also suggest that CAT classroom instruction should be learner-centered and inquiry-oriented; teachers should use the "nondirective language" to guide and boost students' learning. Accordingly, the learning cycle is worth further promoting towards being applied in students' concept learning. Moreover, the mechanism and application strategies of CAT need to be further studied and generalized, the students' learning achievements need to be deeply assessed, so as to make CAT more useful for science classes and learners.