In this study, we examined students' science academic achievement through an analysis of the national assessment of educational achievement(NAEA) from 2015 to 2018 when the 2009 revised curriculum was applied. This study analyzed achievement average scores by gender and region and also analyzed the trend of the rate of achievement level in order to understand the characteristics of students' academic achievement. In addition, we analyzed the characteristics of the affective aspect using a survey of students' attitudes (confidence, interest, value, and willingness to learn) toward science. The main findings are as follows; First, the average science score shows a tendency to decrease year by year at the middle school level. Second, when analyzed by achievement level, the decline in the advanced group was large, and the rate of the below basic group increased. Third, comparisons of the average achievement scores by gender, female students' scores were generally high and the difference in achievement scores between male and female students tended to increase. Fourth, a characteristic gap was found between regional scales that increased in the advanced group. The results of a questionnaire on students' attitudes show that the four constructs of the students' attitudes had a significant correlation with the average achievement scores. In addition, the mean and positive response rates on the confidence, interest, and value of science in the above proficiency group increased but decreased in the below basic group. These results can be used as basic data for revising the curriculum, improving teaching and learning, and establishing educational policies.