國中生放學後看電視時間與學習成就表現的關係，長期以來都沒有進行探討。本研究以基隆市國中生學習狀況資料庫，分析1,585名國中生放學後看電視時間成長軌跡，並瞭解放學後看電視時間對學習成就的影響，從五個學期資料的潛在成長模式分析獲得結論如下：（一）國中生放學後看電視時間成長軌跡呈現W字型變化趨勢，在國一下學期看電視時間最高，隨著學期往後推移，呈現高低起伏，到國三下學期仍不低。可見學生放學後看電視是重要的休閒活動之一。（二）國一生放學後看電視時間愈多，國三下學期學習成就愈不好。而五學期放學後看電視時間成長，對國三下學期學習成就為負向影響，也就是放學後看電視時間成長讓學習成就下降。（三）國一生的放學後看電視時間起始點與後來五學期放學後看電視時間成長幅度為負向顯著關聯，代表國一下學期放學後看電視時間最多，後續至國三上學期有減少。本研究特色在於發現，國中生放學後看電視時間呈現W型成長現象，看電視時間愈多，學習成就愈不好。學生放學後時間應用，學校、家長及學生應有因應策略。針對結論進行討論，提出建議。

The relationship between the time spent watching TV after school and academic achievement performance among junior high school students has not been explored for a long time. This study used the Keelung City Junior High School Students’ Learning Status Database to analyze the growth trajectory of 1,585 junior high school students’ TV watching time after school, and to understand the impact of after-school TV watching time on academic achievement, and obtained conclusions from the analysis of latent growth patterns in five semesters of data as follows: 1. The growth trajectory of TV watching time of junior high school students after school showed a W-shaped trend. The time spent watching TV was the highest in the first semester of the country. As the semester gone on, it showed ups and downs, and it was still not low in the second semester of the third year. It can be seen that watching TV after school was one of the important leisure activities for students. 2 The more time ninth grade students spent watching TV after school, the worse his academic achievement will be in the second semester. The increased in TV watching time after school in five semesters had a negative impact on the academic achievement of the second semester of the third semester, that is, the increased in TV watching time after school reduced academic achievement. 3 The starting point of TV watching time after school in ninth grade life had a negative and significant correlation with the growth rate of TV watching time after school in the next five semesters. The representative country had the most TV watching time after school in the second semester, and it decreased in the last semester. The feature of this study was that it is found that the time spent watching TV after school showed a W-shaped growth phenomenon. The more time spent watching TV, the worse the academic achievement. After school hours are used by students, schools, parents and students should have coping strategies. Discussed the conclusions and make recommendations.