The article shows an overview of Realistic Mathematics Education (RME) and an epistemological analysis of the multiplication of two natural numbers. These results of the study could be considered as fundamental methodological issues relating to teaching the multiplication of two natural numbers to primary students. This is theoretical research. Based on the theoretical framework, we proposed a process of teaching the multiplication of two natural numbers to primary students according to RME. Furthermore, we analyzed and illustrated the process with particular learning activities. Throughout doing these learning activities, under the teacher’s guidance, students will have opportunities to experience mathematizing processes to reinvent mathematics - the multiplication of two natural numbers. It can be seen that the idea of teaching mathematics under the RME perspective is consistent with the current goal of mathematics education in Vietnam. We hope that this article will contribute to introducing an effective approach for teaching mathematics in the orientation of developing learners’ competency