The purpose of this research is to realize the current situation of the Internet activity in junior high school students, to analyze the differences in cyberbullying, motivation and internet addiction among students of different backgrounds, and to discuss the relationship between cyberbullying and movitation, as well as the relationship between cyberbullying and internet addiction. Questionnaire was used as instrument for this study. The data obtained is analyzed with independent t-test, one-way ANOVA, regression analysis and Pearson’s product-moment correlation. There are three major results of this study. First, the more hours students spent on the computer, the more likely they became cyberbullies. Second, among all the motivations, “I read him/her negatively all the time” is the highest. Third, the higher cyberbullying behavior showed, the higher internet addiction appeared.