This study Aimed to Determine the effect of discovery learning models toward the ability of mathematics concepts understanding of the characteristic of geometry in primary school. This research was quasi experiments with quantitative approach. The design was the non-equivalent pretest-posttest control group design. The sampling technique used was cluster random sampling technique in which class VA and VB as the control class and the experiment class respectively. Data of this research were collected through a test. The result of this research showed that the Discovery Learning models had an effect on the students' abilities of mathematics concepts understanding, it was proved by the t-test calculation obtained t_score = 3.21920 and t_table = 2.00172. Thus t_score> t_table, it could be concluded that H0 rejected and H1 accepted.
Discovery Learning Models, Math Mathematics Concepts Understanding