Abstract: Objective To explore the relation of behavior characteristics and brain structure in the first-episode childhood schizophrenia.Methods Totally 96 children with schizophrenia meeting with the criterion of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-Ⅳ) and 49 healthy children were selected as control group one, and another 100 healthy children were selected as control group two.The brain structure of 96 children and 49 healthy children were detected with magnetic resonance imaging (MRI).Achenbach 's Child Behavior Checklist (CBCL) was used to assess social competence and behavioral characteristics of all participants.Results The schizophrenia group had higher transverse diameter of third ventricle, lateral ventricle anterior horn (t = 3.00, 2.13, P<0.05) and lower corpus callosum thickness, caudate head width, hippocampus thickness than the control group (t =-2.44, -7.68, -5.07, P<0.05).Schizophrenia children had higher scores in behavioral problem, social withdrawal, cleavage coercion and offensive factor (Z = 3.00, 2.56, 2.75, 3.67, P<0.05) and lower social competence and school situation compared with control group (t =-4.30, Z = 4.85; P<0.01).Social competence was significantly positively correlated with corpus callosum thickness, gyrus cingulatus, caudate length, the width of the hippocampus and hippocampus thickness.Behavioral problem total scores were inversely correlated with caudate length and the width of the hippocampus.Conclusion The first-episode childhood schizophrenia have lower social competence and more behavioral problems in pre-symptom period.Ventricle enlargement and brain structural abnormalities following onset of the disease are observed.Behavioral problem and the social competence get worse with significant ventricle enlargement and brain structural abnormalities.