In this study, the researcher tried to find out the effect of using a computer interface in teaching speed concept in the elementary school. The 4th and 5th pupils were sampled for this study. The school is located in a sub-urban agricultural area in Korea. In the study, the subjects were divided into two groups: experimental and comparison group. From the pretest, two groups did not show any difference in the understanding of speed concept. The computer interface and the programs to operate the interface and data analysis were developed by researcher. The interface is a modular type and designed ready to connect to microcomputer. The test items were consisted of (1) comparison of speed, (2) change of motion, (3) acceleration, and (4) deceleration. As the result, the researcher found the following results: 1. In case of speed comparison, no significant difference was found between experimental and comparison group. 2. In case of change of motion, acceleration, and deceleration, the experimental groups showed higher achievement both in 4th grade and 5th grade. However, the 4th graders showed more learning than the 5th graders. In conclusion, this study showed that the use of computer interface seemed to be very effective in teaching and learning speed concept in elementary school.