To explore the clinical effect of one-appointment root canal therapy combined with full crown restoration in patients with cracked teeth. Methods A total of 90 patients with cracked teeth admitted to Yuanmei Dental Clinic, Baotun, Houjie, Dongguan from January to December 2019 were selected as the research objects. According to the order of admission, they were divided into control group and observation group, with 45 patients in each group. The control group was treated with multiple root canal therapy combined with full crown restoration, and the observation group was treated with one-appointment root canal therapy combined with full crown restoration. The clinical efficacy, dental aesthetic effect, masticatory function and complications were compared between the two groups. Results The total effective rate of treatment in the observation group was 95.56%, which was higher than 68.89% in the control group (P<0.05). The proportion of good coverage, neat teeth and neutral occlusion of molars in the observation group was higher than that in the control group (P<0.05). After treatment, the masticatory efficiency and bite force of the observation group were higher than those of the control group (P<0.05). The incidence of complications in the observation group was 2.22%, which was lower than 28.89% in the control group (P<0.05). Conclusion The effect of one-appointment root canal therapy combined with full crown restoration in patients with cracked teeth is better than that of multiple root canal therapy combined with full crown restoration, which can effectively improve the bad state of teeth, improve the aesthetic effect of teeth, enhance the masticatory efficiency and bite force, and has fewer complications and higher application safety.