This study aimed to investigate the effect of passing preschool course on boy and girl first grade students adaptive behavior and academic achievement with the intelligence control. The research method was ex-post facto. The populations studied in this research concluded all first elementary school boys and girls students(N= 1800) in Behbahan city in the academic year of 2012-2013 . The study sample consisted of 320 first grade students selected by stratified sampling technique . They were divided into two groups of students who have passed the pre-school period (160 total, 80 boy and 80 girl ) and the students who have not passed it (160 total, 80 boy and 80 girl ). The Rutter Children’s Behaviour Questionnaire (Rutter, 1967) is a form by behavioral problems children aged between 6 to 13 identified by teachers or parents was completed by only teachers in this study . student academic performance was measured through their correct answers to the standard questions developed by Department of Education with regard to content and purpose of the training of first class . Raven’s colored Progressive Matrices Test ( Raven et al., 1990) was also used in this research . Results showed that first-grade girl students who have passed the pre-school had significantly higher academic performance and adaptive behavior than those students who have not passed with the intelligence control . Similarly , significant difference was found between first-grade boy students who have passed the pre-school and the students who have not passed it in terms of academic performance and adaptive behavior with controlling IQ. Key words: Preschool course, Academic Achievement, adaptive behavior intelligence