Although many researchers are mentioning about content on significance of physical environment for crime prevention, it is true there is lack of empirical researches dealing about interrelationship between crime and physical urban environment. This research studied on the interrelationship between sexual crime targeted on children and teenagers and physical urban environment factors with Seoul being the background where crime occurs most frequently. Percentage of children and violence showed negative interrelationship, and percentage of single parent household and rate of sex crime targeted on children and teenagers showed positive interrelationship. In contrast to the fact the rate of sex crime targeted on children and teenagers showed positive interrelationship with industrial areas. The more the number of schools the higher the rate of sex crime targeted on children and teenagers. The meaning of the major result lies on understanding the relationship between crime and urban design which had been insufficient in conventional studies, by showing a new result of the role of urban design in of preventing sex crime targeted on children and teenagers for efficient strategies and measures of crime prevention.