This study is attempted to define risk factor of youth runaway impulse and to structure forecast model through an extensive analysis of the factors influencing the runaway impulse of youth. The subjects were 610 high school students in Seoul and Kyunggido. The collected data was analysed by SAS. The differences between the runaway impulse group and the non-runaway impulse group were subject to chi-square and t-test. Also logistic regression analysis was conducted on the basis of purposeful selection method for constructing the forecast model. The findings are as follows : the major predicting factors of youth runaway impulse are sex(odds ratio=1.886, p=.009), existence of friends of the opposit sex(odds ratio=2.011, p=.007), anti-social personality(odds ratio= 4.953, p=.000), depressive trend(odds ratio= 2.695, p=.000), family structure(odds ratio= 5.381, p=.000), marital relationship(odds ratio =1.893, p=.009) and also between parents and youth(odds ratio=3.877, p=.000), emotional abuse(odds ratio=1.963, p=.003), authoritative controlled rearing(odds ratio=2.135, p=.005) and stress from school(odds ratio=1.924, p=.008). Therefore, the forecast model will be contribute to the nursing intervention for prevention of runaway youth.