[[abstract]]This study aims to explore the effects of reflection behaviors (category and performance) on learning to use the Web-based Portfolio assessment. Experimental subjects were 30 second grade students in a Computer Application course at a senior high school. The Chinese Phrase Processing System was used to distinguish phrases of students’ reflections. Based on the processing results, students’ reflections were classified. Performance of reflection consists of the number of words in the reflection, amount of reading peer reflection, time of reading peer reflection, and grade of reflection. Research results show that the reflection category and number of words in reflection do not have a significant effect on learning performance (work, test and attitude). The number of reading in peer reflection shows a significantly positive effect on attitude, but do not show significant effects on the performances of work and test. Time of reading peer reflection shows significantly positive effects on work and attitude but do not show significant effects on test performance. Grade of reflection shows a significantly positive effect on work, test and attatude. Comparisons among the three effects of reflection category and four reflection performances on learning exhibits different effect sizes. As a whole, the effect on attitude is highest; and work is the second. Time on test was the lowest.