This study investigates influence of parental attachment on school adjustment using self-perceived competence as a mediating variable for perceived school age children. The subjects were 760 children who are 4, 5, and 6 grades in 4 elementary schools at Daegu. The collected data were analyzed by single and multiple regressions that used SPSS win 19.0 The results were as follows: (1) The parental Attachment perceived by school-age children was positively associated with on school adjustment. The parental attachment level of school-age children becomes higher as the perception of school adjustment increases. (2) The parental attachment perceived by school-age children was positively associated with self-perceived competence. That is, the parental attachment level of school-age children becomes higher as the self-perceived competence increase. (3) The effect of parental attachment in the school adjustment by children was reducing explanation when controlled for the self-perceived competence. The Parental attachment that influenced the school adjustment is partially mediated by self-perceived competence. The results of this research indicates that both the quality improvement of inter-relationship between children and parents for school adjustment of school-age children and training for strengthening self-perceived competence of school-age children are important.