Research objectives: 1) To determine the development of Islamic Religious Education teaching materials in improving understanding of Al-Islam in SDIK Akhlakul Karimah Sudiang, Biringkanaya District, Makassar City. 2) To determine the level of understanding of Al-Islam in SDIK Akhlakul Karimah Sudiang, Biringkanaya District, Makassar City. This research uses a qualitative method. The data needed in this study are in the form of observation, interviews, and documentation. All data collected are analyzed in the form of data reduction, data presentation, and drawing conclusions. The results of this study indicate that 1) the development of Islamic religious education teaching materials in improving the understanding of Al Islam in students of SD Islam Karakter Akhlakul Karimah Sudiang, Biringkanaya District, Makassar City is carried out by referring to the 2013 curriculum that has been set by the Ministry of Education which includes textbooks, online materials and scientific articles then educators also try to develop teaching materials by educators attending workshops to update teaching methods which include designing lesson plans, developing content and compiling questions and making interesting presentations. 2) the level of understanding of Al Islam in students of SD Islam Karakter Akhlakul Karimah Sudiang, Biringkanaya District, Makassar City through the development of teaching materials and evaluations such as daily tests, assignments and direct observation and questions and answers, the level of student understanding in general is good with most students being able to master the basic material of education about Al Islam but there are some students who still need further guidance in the concept of Al Islam education.