【Abstract】Objective: To analyze the efficacy and esthetic effect of metal preformed crown restoration in children with dental defects of primary m. Methods: The research sample was selected from children with dental defects of primary molar treated in our hospital from January 2024 to June 2025,ing 120 cases. Random number table method was used to divide into the control group (60 cases) and the experimental group (60 cases). The treatment of occlusal ability, masticatory efficiency, esthetic effects, the incidence of complications and parental satisfaction were compared between the two groups after treatment. Results: There was no difference in occlusal ability, masticatory efficiency and PES, WES scores of the two groups of children before restoration (P>0.05). After restoration the maximum occlusal area, maximum occlusal force, masticatory efficiency, PES and WES scores, the success rate of restoration and parental satisfaction of the experimental group were higher than those of the control group (P<0.05). In addition, the incidence of complications in the experimental group was lower than that in the control group (<0.05). Conclusion: Metal preformed crown restoration of dental defects of primary molar in children can effectively restore and improve occlusal function and masticatory, while showing significant advantages in esthetic effects, the success rate of restoration and parental satisfaction, and the incidence of complications is lower.