Objective To analyze the clinical value of vital pulp amputation combined with metal preformed crown restoration for class Ⅱ cavity in primary molar. Methods A total of 30 patients with Class II cavity in primary molar admitted to People's Hospital of Anshun City from January to August 2024 were selected as the research subjects, and they were divided into control group and observation group according to the random number table method, with 15 patients in each group. The control group was treated with intraoral direct filling restoration, and the observation group was treated with vital pulp amputation combined with metal preformed crown restoration. The clinical efficacy, occlusal function, periodontal condition [gingival index (GI), plaque index (PLI)] and complications were compared between the two groups. Results The total clinical effective rate of the observation group was 93.33%, which was higher than 80.00% of the control group (P <0.05). The maximum occlusal contact area and maximum occlusal force in the two groups at 3 months after treatment were higher than those before treatment, and those in the observation group were higher than those in the control group (P <0.05). The GI and PLI in the two groups at 3 months after treatment were lower than those before treatment, and those in the observation group were lower than those in the control group (P <0.05). The incidence of complications in the observation group was lower than that in the control group (P <0.05). Conclusion The clinical effect of vital pulp amputation combined with metal preformed crown restoration for class Ⅱ cavity in primary molar is better, which can better restore occlusal function, improve periodontal condition and reduce the incidence of complications.