Driven by the elementary students' low self-efficacy (SE) in learning mathematics, this study aims to delve deeper into the interaction between learning based on Mathematical Prior Ability (MPA) and the improvement of students' SE after the implementation of Concrete-Pictorial-Abstract (CPA) approach. In total, 119 elementary school students from Purwakarta, Subang, Karawang dan Bekasi participated. Both tests and non-tests were used as the instruments of this study. Using a quasi-experimental design with a nonequivalent pretest-posttest control group, a two-way ANOVA was used as the technical analysis of the data. The research results revealed that the learning factors are higher than 0.05 i.e. (0.235), the significance of the MPA factor is smaller than 0.05 i.e. (0.030), and the significance of the interaction factor (Learning MPA) is higher than 0.05 i.e. (0.301). It can be concluded that there is an interaction between learning (CPA and conventional) based on MPA and the students' SE. Thus, the CPA approach can be used to enhance the students' SE so that they can learn with higher confidence.