. Learning fractions is one of difficult topics for students with visual impairments. The aim of this design research is to describe the design process of Hypothetical Learning Trajectory for the addition of fractions using Fraction Block Braille. This research is divided into 3 stages, the preparation for the experiment, the design experiment, and the retrospective analysis. Data collection techniques in this research are walkthrough, observation, interview, and test. This research resulted in a Hypothetical Learning Trajectory design for the addition of fractions contains the following activities: Dividing unit blocks into equal parts, Comparing the sizes of different fraction blocks to get the same size fractions, Comparing the combined sizes of several blocks, Combining several fractions, Determining the fractional block that is the same size as the summed fraction block. The five activities were carried out quite well in the 2-cycle experimental activity. After the implementation of the experimental activities, the students' answers to the practice questions showed that the research subject could understand the material presented.