The main purpose of this study was to investigate the mathematical learning effects of dynamic assessment on resource room students at the junior high school level. The participants consisted of 48 resource room students from two junior high schools in Tauyuan county. The results indicated that there were significant differences in both the post-test and post-post-test scores for the treatment group and comparison group. Therefore, the researchers suggest that the learning potential assessment device is helpful for math resource room teachers who are seeking a more effective way to both assess and scaffold special education students' abilities.