Private university students in Taiwan often face the pressure of student loans and high cost of living, so they tend to work part-time while going to school. Skipping classes in order to work part-time might lead a student to decrease student engagement, which, in turn, affects academic achievement. The purpose of this study is to test whether reading engagement has a moderating effect on student engagement and academic achievement. We collected data from 4,495 Asia University students’ absenteeism rate, book borrowing records and academic performance, and then conducted empirical analysis using hierarchical regression methods. Research findings are as follows: 1. The higher the number of absenteeism, the worse the class ranking results. Therefore, we should face up to the problem of low student engagement of Taiwan’s college students and formulate strategies to improve student engagement. 2. Those who have borrowed books are 2.3 times more likely to be ranked the top half in their class than those who have not borrowed books. Therefore, strategies for improving reading engagement should be devised and integrated into teaching. 3. The method of using reading engagement to improve academic performance is more effective with high absenteeism rate students than with low absenteeism rate students. Therefore, low absenteeism rate students should be strictly required to increase their attendance rate and high absenteeism rate students should be assisted with more reading engagement.