This study was aimed to analyze the ability of mathematical representations in the eighth-grade junior high school students by using the REACT strategy on the learning of Realistic Mathematics Education (RME). The REACT strategies represent Relating, Experiencing, Applying, Cooperating, and Transferring. This study was a quasi-experimental research with nonrandomized pretest-posttest control group design. The population of this study was students in the eighth grade. Two classes were selected and classified as a class of experiments (with RME approach by REACT strategy), and control class (with scientific approach). Data obtained was analyzed by the independent t-test and proportions test. The results showed that there was an interaction between the approaches of RME with REACT strategy on the ability of mathematical representation. The students with approach RME by REACT strategy had better representation ability than the students with current approach scientific. In addition, it was found that more than seventy percent of students with RME approach by REACT strategy fulfill the learning completeness.