Objective To explore the effect of bracketless invisible appliance on occlusal function and periodontal indexes in children with class Ⅲ malocclusion. Methods A total of 80 children with dental class Ⅲ malocclusion admitted to our hospital from November 2020 to November 2022 were selected as the research subjects. According to the different application of orthodontic appliances, they were divided into the control group and the observation group, with 40 children in each group. The control group was treated with straight-wire appliance, and the observation group was treated with bracketless invisible appliance. The clinical efficacy, treatment time, occlusal function, periodontal indexes and adverse reactions were compared between the two groups. Results The total effective rate of treatment in the observation group (97.50%) was higher than that in the control group (82.50%) (P <0.05). The tooth leveling time and occlusion opening time in the observation group were shorter than those in the control group (P <0.05). After treatment, the occlusal contact time in the observation group was shorter than that in the control group, and the maximum occlusal force was greater than that in the control group (P <0.05). After treatment, the SBI, PLI and PD in the observation group were lower than those in the control group (P <0.05). The incidence of adverse reactions in the observation group (5.00%) was lower than that in the control group (20.00%) (P <0.05). Conclusion The application of bracketless invisible appliance in class Ⅲ malocclusion can improve the total effective rate, shorten the orthodontic improvement time, further improve oral occlusal function and periodontal health, and has fewer adverse reactions.