Objective To explore the effect of combined use of vitamin D and atomoxetine hydrochloride on children with attention deficit hyperactivity disorder(ADHD)and its impact on their behavioral dysfunction and neurological damage. Methods A total of 105 children with ADHD treated in the hospital were included from July 2023 to March 2024. They were divided into control group with 52 cases treated with atomoxetine hydrochloride, and observation group with 53 cases treated with vitamin D combined with atomoxetine hydrochloride using a computerized grouping method. The clinical efficacy, neurological function, behavioral function, and adverse reactions were observed in both groups. Results The total effective rate of the observation group(96. 23%)was higher than that of the control group(78. 85%)(P<0. 05). After treatment, compared with the control group, the levels of neuron-specific enolase in the observation group were significantly lower in terms of behavior, learning, physical fitness, impulsivity hyperactivity, anxiety and hyperactivity index scores(P<0. 05). The comparison of the incidence of adverse effects between the two groups was not significant(P>0. 05). Conclusions The combined use of vitamin D and atomoxetine hydrochloride has a more significant therapeutic effect on children with ADHD, which can effectively alleviate behavioral dysfunction, reduce neurological damage, and has good safety.