This paper aims to explore the application and exploration of constructivism educational theory in the practice of primary school mathematics curriculum reform. Constructivism educational theory emphasizes student-centeredness, focuses on students' subjectivity and initiative, and advocates the construction of knowledge through students' practical activities. By analyzing the existing problems in the current primary school mathematics curriculum and combining the core viewpoints of constructivism educational theory, this study proposes a series of reform measures and conducts practical exploration in actual teaching. The research results show that the reform of primary school mathematics curriculum under the guidance of constructivism educational theory can effectively improve students' interest in learning, autonomous learning ability, and mathematical thinking ability, which has positive significance for promoting the overall development of students.
