Recently, most people in the world are using smart phones. People can check daily weather, chat with friends, and play games. That means that there are no impossible things with smart phones. Therefore, people can live more convenient because they don't have to do and work separately. However, at some points, they addict to use smart phone. From my experience, when I walk in my school, I can see the most students and professors are using smart phones; and they are always looking their phones screen. As a result, people need to use phone lesser than now. For more information and opinion, I did a little survey to college students. The first survey question is that how often do you use your phone a day; and please write what application do you use most time. Exactly everyone checked in the ‘every day’. Four people put that they are using phone mostly to watch video. Another four people put they are using phone mostly to read book, play game, and others. And then other, twelve people, mostly plays the social networking as Facebook, Weibo, Snapchat, and KaKao Talk. Also, they said they are spending more time with phones than the time that they are spending with their friends. For this, there will have problem with social communication between people. Second, the second survey question is that how long do you spend with your smart phone in once; and please write a comment for more specific information. The six students chose the ‘more than five hours a day’. That means they spend 30 percent of their day life with little smart phone. They are students and they have to study for the college class. If they spend with phones like the survey’s result, their study time caught by the smart phones. Some comments are saying that they know they have to study for the tests and the quizzes, but they cannot control. It is very scary to hear that they cannot control those. To prevent these problems, they need to use smart phone less time. It is impossible to not use the