This study aims to develop a knowledge structure based digital individual learning content and computerized adaptive testing(BNAT) which is about addition and subtraction on decimals in the Fifth Grade. It lets teachers have adaptable adaptive testing after teaching. We hope it can reach significant effect on meeting students’ individual needs and testing students’ individual abilities.Results: 1. The number of items administrated by BNAT is 18.5. 11.5 items are omitted and prediction accuracy can reach 92.96％~97.26％. 2. After the teaching and adaptively remedial instruction with digital individual learning content, students have significant progress on their grades. It shows that this digital individual learning content is valuable for using. 3. This digital individual learning content is adaptable to two kinds of teaching models, and the study shows that individual instruction will have great effect. 4. In point of the sex, the boys taught by the teaching model of individual instruction have the greatest progress. In point of the student’s ability, the students of the middle mark group and the low mark group get more grades than the high mark group. Bye the way, taking individual teaching is better than group teaching among the middle mark group and the low mark group.