Objective To understand the general situation of mental development of children with suspected mental retardation,in order to provide scientific evidence for early screening and timely intervention.Methods A total of 2 178 children with suspected mental retardation who completed the Gesell Developmental Scale were enrolled at West China Second Hospital in this study from 1st January,2014 to 1st January,2017. The mental development was assessed by Gesell Development Scale,and the developmental quotient was analyzed. Results Totally 1 979 children with completed data were analyzed,of which 1 514(76.5%) were boys and 465(23.5%) were girls. The proportion of boys was significantly higher than that of girls at different month groups(χ²=44.652,P＜0.05). The proportion of developmental defects in language area was 86.2%,and it was 68.6%,68.0%,57.3% and 52.8% in adaptive behavior,personal-social behavior,fine motor and gross motor area,respectively. The proportion of developmental defects in language area of boys was higher than that of girls(P＜0.05). Correlation analysis indicated that there were significant positive correlations between the degree of developmental defects in language area and the degree of developmental defects in adaptive behavior,personal social behavior,gross motor and fine motor area(r=0.731,0.795,0.676,0.690,P＜0.001). Conclusions Language developmental defects are prominent in children with suspected developmental retardation,which are comorbid with different degrees of developmental defects in other functional areas. In particular,attention should be paid to the language development of boys. Therefore,the early intervention of comprehensive mental development based on the language development should be the focus of clinical work right now.