Objective To explore the aesthetic effect of all-ceramic full crown and onlay for restoration of low molars and the influence on masticatory function. Methods From June 2023 to January 2024, 60 patients with low molars admitted to Hedong District Tangtou Street Gegou Health Center were selected as the research subjects. They were divided into control group and observation group by the random number table method, with 30 patients in each group. The control group was given all-ceramic full crown restoration, and the observation group was given onlay restoration. The restoration effect, masticatory function, aesthetic effect and quality of life were compared between the two groups. Results The restoration excellence rate in the observation group was 90.00%, which was higher than 73.33% in the control group (P <0.05). The masticatory efficiency and occlusal force in the observation group were better than those in the control group at 3 and 6 months after restoration (P <0.05). The PES and WES scores in the observation group were higher than those in the control group at 3 and 6 months after restoration (P <0.05). The GQOL-74 score in the observation group was higher than that in the control group (P <0.05). Conclusion Compared with all-ceramic full crown restoration, onlay restoration for low molars has better effect and aesthetic effect, which can improve masticatory function and quality of life, and it is worthy of clinical application.