This research aimed at establishing a Computerized Adaptive Diagnostic Test(CADT) and remedial instruction based on the structure of competence indicators, using the “Algebra and Statistics ” of Mathematics in Grade 3 as an example. After taking the test, students were diagnosed and given the remedial instruction effectively according to their achievement in competence indicators and the concept nodes of knowledge structure. The items of this research were based on the knowledge structure established through the experts’ and teachers’ analysis of the competence indicators. After the written test, both the student items structure and the CADT Item Bank were established according to the OT and SS. After the CADT, students could conduct the remedial instruction on their own weaknesses of the competence indicators. This research had the following findings: 1. The CADT based on the structure of competence indicators could effectively save the time and items needed in a test. 2. The items of this test could effectively distinguish the achievement of competence indicators for students. 3. This Computerized remedial instruction could combine testing and remedial instruction consistently and make learning effective.
