The purpose of  this study was identify on the relationship between socialization systems and sport fanaticism for Saudi fans in Riyadh city, the  this study this study was conducted on (855) fan of Saudi fans by using the descriptive style, a survey was used in this study including on: (demographic information, sport fanaticism survey and socialization systems survey), the most important results that sport fanaticism level for Saudi fans in Riyadh city was below than middle level, also there was the influence for some of socialization systems (family, school, friends group, media, sport hero, sport clubs) on sport fanaticism, and the sport fanaticism level for the study sample related to age variable was below than the middle level, and the sport fanaticism level of the sample in a changing educational level was middle. There were significant differences in the scores total for sport fanaticism scale depending on the different in social situation for unmarried persons, there are significant differences in sport fanaticism scale for persons who have high economic level, also there were significant differences for persons who were practiced practice for sports activities affected on sport fanaticism but were less than the middle level. This study had several recommendations; the most important was taken procedures toward role of socialization systems - for reducing from spread of sport fanaticism in Saudi society in the future.