Objective To investigate the effect of different birth styles on the children's intelligence. Methods Using the Chinese Ages and Stages Questionnaires questionnaire (ASQ-C) for parents/guardians of the children aged one, according to birth style, the children were chosen and divided into 2 groupsnaturally delivered group and cesarean delivered group, to investigate the effect of mode of delivery on children's intelligence.SPSS 17.0 was used to analyse. Results There was no significant difference between boys and girls of the intelligence (t=0.017, P>0.05).The CG and PS scores in urban and country were different (t=2.418, P<0.05) .The scores of CM and GM of urban children were higher than the country-children, there were no significant differences among the FM, CG and PS (P>0.05).There was obvious difference between the spontaneous delivery group and the cesarean section group (t=3.039, P<0.01), the scores of CM, FM and PS of the spontaneous delivery group was higher than the cesarean section group (P<0.01), but there were no obvious differences between the GM and CG(P>0.05). Conclusions The intelligence of children is no difference in gender, residence was the factor of intelligence.The cesarean section is a risk factor to the intelligence of children.