Objective To analyze the restoration effect of mineral trioxide aggregate (MTA) on preservation of activated pulp of young permanent teeth. Methods A total of 84 young patients with permanent tooth pulp preservation admitted to our hospital from January 2020 to January 2021 were selected as the research objects and randomly divided into two groups, with 42 cases in each group. Group A was treated with MTA repair, and group B was treated with apexification.The total effectiverate, periapical index (PAI), dental pulp stem cell (DPSCs) absorbance, normal ratio of pulp vitality test and adverse reaction rate were compared between the two groups. Results The total effectiverate of group A was higher than that of group B, and the differencewas statistically significant(P<0.05). The PAI of group A was mainly grade 1, and that of group B was mainly grade 2, there was significantdifferencein the proportion of PAI grade 1 and grade 2 between the two groups (P<0.05). The absorbance of DPSCs at different time points in groupA was higher than that in group B, the normal ratio of pulp vitality test was higher than that in group B, and the total incidence of adverse reactions was lower than that in group B, and the differencewas statistically significant(P<0.05). Conclusion MTA repair can protect the periapical function of teeth and improve the pulp vitality, which has high repair safety and effectiveness