Objective To explore the effect of micro root canal therapy combined with ultrasonic technique in the treatment of irreversible pulpitis. Methods A total of 60 patients with irreversible pulpitis admitted to our hospital from January 2022 to January 2023 were selected as the research objects. They were divided into combined group and conventional group by random number table method, with 30 patients in each group. The combined group was treated with micro root canal therapy combined with ultrasonic technique, and the conventional group was treated with conventional root canal therapy. The quality of life score, language function and masticatory function score, treatment time and anesthesia onset time and complication rate were compared between the two groups. Results The scores of quality of life in the combined group were higher than those in the conventional group, and the difference was statistically significant ( P <0.05). The scores of masticatory function and language function in the combined group were higher than those in the control group, and the differences were statistically significant ( P <0.05). The treatment time of the combined group was longer than that of the conventional group, and the onset time of anesthesia was shorter than that of the conventional group, the differences were statistically significant ( P <0.05). The incidence of complications in the combined group was lower than that in the conventional group, and the difference was statistically significant ( P <0.05). Conclusion Micro root canal therapy combined with ultrasound technology is effective in the treatment of irreversible pulpitis, which can promote the recovery of masticatory function and language function, shorten the anesthesia time, reduce the incidence of complications, and improve the quality of life of patients. It is worthy of clinical application.