This research was carried out to examine the family system types and the separation-individuation procedures, which seriously affect the mental development of middle school students. The research analysed the rate of separation-individuation in each family system types, as well. The resets of this study are as follows: 1. The midrange family was 61.1% among the four family system types, recognized by the middle school students. 2. Most of the middle school students were suffering from the separation-individuation procedures. And the most afflicted hardship was the dependency denial, which was followed by the reject expectancy and self-centeredness. 3. The girl students were more deeply affected by the family system types than boyhood. Therefore girl students were much more intimate with family and made very stagnant progress on the separation-individuation procedures .