This research is motivated learning phenomenon obstacle concept of fractions in fourth grade student. Research using DDR design. The purpose of this study to explore the learning obstacle, designing didactic design, implement and analyze the process and results of the implementation design. Data was collected by documentation, interviews, tests and observation. The research findings reveal the five types of barriers to learning students on the concept of fractions. Didactic design that was developed consisting of 4 lesson design and implement learning in third grade elementary school. The implementation results show the tendency of students in a particular response. Most students can achieve learning objectives are set, which means this didactic design can accommodate students' learning trajectory.