Objective To explore the application effect of root canal microscopy combined with ultrasound in the treatment of dental pulp. Methods From February 2017 to February 2019, 93 patients with dental pulp disease treated in our hospital were selected as the research subjects. They were divided into the reference group (n=46) and the study group (n=47) according to the random digital table method. The patients in the control group were treated with root canal therapy in a routine way, while the patients in the study group were treated with root canal microscope combined with ultrasound. The operative time and anaesthesia time of the two groups were recorded, the clinical effect and the adverse reactions of the two groups were compared. Results The operation time, the anaesthesia time of the patients in the study group were longer than those in the control group, the differences were statistically significant (P＜0.05). The total effective rate of treatment in the study group was 91.49%, which was higher than that in the control group(91.49%), the difference was statistically significant (P＜0.05). The total incidence of adverse reactions in the study group was 6.38%, which was lower than 26.09% in the reference group, and the difference was statistically significant(P＜0.05). Conclusion Compared with common root canal therapy, root canal microscopy combined with ultrasound in the treatment of dental pulp disease is more effective, and the incidence of complications is lower, but the treatment time is longer.