The followings are Online Safety Issues in my class this year. First, there is a student A who spends a lot of time playing online games and watching YouTube during the day. He stays home alone playing games and watching YouTube until late at night. As a result, there are frequent situations in which he is always late for class due to lack of sleep time and cannot concentrate on classes in the morning. Second, there is a student B who is addicted to adult content. He has been browsing adult content on his cell phone with his friends in the restroom during his break at school. A serious cyber sexual violence problem occurred by forcing a friend who did not want to watch adult content. Third, student C said slanderous words to other students on Facebook and Instagram, which are social networks with age restrictions, and released this article for unspecified people to read. Online safety issues of these students can be solved only when parents actively manage and control students' digital devices and Internet accounts at home. But Students A, B, and C above are children of low-income families and multicultural backgrounds. The parents have no time to spare due to economic problems and have difficulty communicating. Therefore, the parents do not know the seriousness of their children's online safety issues and have no interest in them. It is also difficult for them to attend parent training to inform or improve the seriousness of this problem, and to understand the contents even if they can attend. These problems will become more serious and accelerated in conjunction with the digitalization of education promoted by COVID-19. If we don't take this problem seriously and try to solve it now, it will be even more difficult to solve it.