Nowadays junior high school students addict to Internet have been common; as of the trend of its popularization. Statistics suggest that, by MOC, the ratio of surfing on the internet reach to 91.19%; among of them 12 percents spend 2 hours on the computer every day by the other cases study. This question is worth to research and discussion in the future. The internet activity indirectly results to decline the body function owing to its sedentary life style. The statistic figures said that the male junior high school students increase BMI value year by year and female students do obviously less well than before on the sit-ups. It is deserving of further investigation if those students who are addicted to internet caused their health fitness deteriorated. For the investigation of the relation between internet addiction and health fitness, picks up 483 students for case study on the theory basis of Young(1998) measure table and Health Fitness Grade Comparison, MOE; makes use of variation analysis and Chi-square understanding both connection. The research points out that the more addiction to internet, the worse health fitness, among them males are addicted to internet easier to females. Most of Grade 8 & 9 students are addicted to the medium & high-intermediate internet; they like to play on-line games. Most of the addiction populations are the 14-year-old high-intermediate grade students. The more average weekly time spend on the internet, the more addiction to that. They prefer to play at home and Internet Caf?; average weekly consumption amount is from NT$ 701 to NT$ 1,050. The higher ration numbers addict to internet, the higher ratio numbers refer to the entertainment and information; on the contrary, the lower ratio numbers wish to learn how to use email, how to search data for work , how to shopping on the computer and so on.
