Objective To investigate the chromosomal characteristics of children with global developmental delay (GDD) and analyze the influencing factors of prognosis of children. Methods 181 children with GDD admitted to Children’s Hospital of Hebei Province from January 2018 to May 2021 were selected as the research subjects. All the children received whole exome sequencing+copy number variations (CNVs) detection, and their chromosomes were analyzed. All children were followed up for 1 year, and were divided into poor prognosis group and good prognosis group according to their prognosis. The baseline data of children in the two groups were compared to analyze the influencing factors of prognosis of GDD children.Results CNVs were detected in 59 of 181 children with GDD. The detection rate was 32.60%. Among them, the pathogenic CNVs were 25.41%, the probable pathogenic CNVs were 5.52%, the clinically unknown CNVs were 1.66%, and the benign CNVs were 67.40%. After 1 year follow-up, 142 (78.45%) of 181 children had poor prognosis after treatment. The age of first diagnosis in the poor prognosis group was higher than that in the good prognosis group, and the proportion of neonatal jaundice, premature delivery and neonatal hypoxic ischemic encephalopathy (HIE). The pathogenic CNVs in the poor prognosis group was higher than that in the good prognosis group, the difference was statistically significant (P<0.05). There was no statistical significant difference in other baseline data between groups (P>0.05). Through Logistic regression analysis, the results showed that, old age at first diagnosis, neonatal jaundice, premature delivery, HIE and pathogenic CNVs were the risk factors for poor prognosis in children with GDD (OR>1, P<0.05). Conclusion Chromosomal analysis by whole exome sequencing+CNVs can identify the genetic etiology of GDD children, and the possible risk factors for the prognosis of GDD children are age at first diagnosis, neonatal jaundice, preterm birth, HIE and pathogenic CNVs