〔Abstract〕 Objective The differences of cognitive impairment between children with attention deficit hyperactivity disorder(ADHD) and normal children were compared, the influencing factors of cognitive impairment of children with ADHD were analyzed. Methods A total of 133 children with ADHD were selected as the ADHD group, and 117 normal children were recruited as the control group. The severity of the subjects′ clinical symptoms was assessed using the Swanson, Nolan,&Pelham Rating Scale-Fourth Edition(SNAP-IV) and the Weiss Functional Impairment Rating Scale. The degree of cognitive functional impairment of subjects was assessed using the MATRICS cognitive suite(MCBB), and the executive function impairment of the subjects was assessed by the Behavior Rating Inventory of Executive Function(BRIEF). The differences in cognitive functional impairment of the two groups were compared. The children with ADHD were further divided into three groups according to their clinical phenotype and age, respectively, and the differences of cognitive impairment among the three groups were compared. The influencing factors of the degree of cognitive impairment in children with ADHD were analyzed by multiple linear regression. The improvement of methylphenidate sustained-release tablets on cognitive and executive functional impairment in children with ADHD was observed. Results The scores of SNAP-IV, Weiss Functional Impairment Rating Scale, connection test and BRIEF of ADHD patients were significantly higher than those of normal controls(P<0.05). The scores of symbol coding test and maze test of ADHD patients were significantly lower than those of normal controls(P<0.05). The score of symbol encoding test in children with ADHD-HI was significantly higher than that in ADHD-I and ADHD-C groups(P<0.05), and the total BRIEF score of ADHD-C was significantly higher than that in ADHD-I and ADHD-HI groups(P<0.05). With the increase of age, the score of connection test of ADHD children gradually decreased, while the scores of symbol coding test and maze test gradually increased(P<0.05). The results of multiple linear regression analysis showed that age was the influencing factor of ADHD children′s score in the connection test, symbol coding test and maze test(P<0.05); the scores of SNAP-IV and Weiss Functional Impairment Rating Scale were the influencing factors of BRIEF score of ADHD children(P<0.05). After methylphenidate treatment, the scores of connection testand BRIEF significantly decreased(P<0.001), while the scores of symbol coding test and maze test significantly increased(P<0.001). Conclusion The younger the age and the more serious the clinical symptoms related to ADHD suggest that the cognitive impairment of children with ADHD is more serious. After methylphenidate treatment, the degree of cognitive and executive impairment in children with ADHD are improved.