This study aimed to enhance elementary-school science teachers' understanding of astronomy concepts including season, moon phase and eclipse by using and building scientific models. Twenty-nine elementary-school science teachers from Udon Thani, Thailand participated in this study in 2014. The teaching sequence was designed to address difficult astronomy concepts. Firstly, questions of the astronomy phenomena were asked. After common misconceptions were answered, teachers become dissatisfied with the old conceptions. Then, scientific models were presented and explained. Finally, science teachers built scientific models to explain the astronomy phenomena. The research design of this study was one group pre-test-post-test design. Twenty-five questions from an astronomy test were used to access teachers' understanding of the concepts. The data were analysed using the mean score, percentage, standard deviation and t-test for dependent samples. It was shown that the average percentage of correct answers before and after the teacher training programme were 32% and 58%, respectively. The post-test mean score was significantly higher than the pre-test score. These findings lead to the suggestion that teaching astronomy concepts by building scientific models and using them can be a meaningful learning activity in the science classroom.