The study is aimed to be well aware the survey of junior high students' behavior of the mobile phone use, the differences of their mobile phone use behavior based on their different background, and its connection with interpersonal relationship and parent-children interactions. The questionnaire investigation method is used to collect information. The study involves junior high school students from Grade 1 to 3 of 2011 academic year in Tainan City. The main results are as followed:1. Over 80% of the parents are in favor of the children to use mobile phones. Most of the junior high school students' cellphones are gifts from their parents; the largest proportion of the length of years holding a cellphone is one to two years. The main reason of using the phone is to contact certain person conveniently. 75% of the students control their monthly phone bills under 400 dollars; about 80% of the students' cell phone charges are paid by the parents. The period of time using cell phones are between 5 p.m. to 11 p.m. The most frequently used phone functions are messages, music players, alarm clock, and phone calls. The students mostly make contact with their parents and then secondly their school friends and classmates.2. No significant difference of mobile phone use behavior is found among different grades of junior high school students.3. Different gender of junior high students shows significant differences on the aspects of mobile phone addiction and an expression of personal style.4. The junior high students with different parents' attitudes show significant differences on the aspects of mobile phone addiction.5. The junior high students with different types of mobile phones show significant differences on the aspects of mobile phone addiction and impact.6. Junior high students' behavior of the mobile phone use illustrates positive correlation with interpersonal relationship and parent-children interactions.