Objective: To explore the efficacy and safety of different doses of vitamin D combined with multi-sensory stimulation in the treatment of universal developmental delay (GDD). Methods: Clinical data of 118 children with GDD who were treated in the pediatrics department of Baofeng County People"s Hospital from May 2020 to April 2023 were retrospectively selected, and they were divided into high-dose group (n=40), medium-dose group (n=39) and low-dose group (n=39) according to drug dosage. All three groups were treated with vitamin D combined with multi-sensory stimulation. The low-dose group was supplemented with 500 IU of vitamin D daily, the medium-dose group with 2000 IU of vitamin D daily, and the high-dose group with 4000 IU of vitamin D daily. All three groups were treated for 6 months. The intelligence level, motor function, vitamin D level and complication rate of the three groups were compared. Results: After treatment, the level of intelligence, motor function and vitamin D in high-dose and medium-dose groups was higher than that in low-dose group, and the incidence of complications was lower than that in low-dose group (P<0.05). The high dose group was better than the medium dose group (P<0.05). Conclusion: Compared with medium-dose and low-dose vitamin D, high-dose vitamin D combined with multi-sensory stimulation can improve motor function and intelligence of children with GDD, and it is safe and reliable.