Objective To evaluate the efficacy and safety of cavitron ultrasonic surgical aspirator in the treatment of fat accumulation in the nape and upper back. Methods A total of 66 patients with fat accumulation in the nape and upper back admitted to Shenzhen Jumei Boyue Medical Beauty Clinic from January 2023 to October 2024 were selected as the research subjects. According to the random number table method, they were divided into the reference group and the study group, with 33 patients in each group. The reference group was treat with routine liposuction, and the study group was treat with cavitron ultrasonic surgical aspirator. The subcutaneous fat thickness, operation time, ecchymosis regression time, fat accumulation improvement rate, aesthetic satisfaction rate and complications were compared between the two groups. Results After treatment, the subcutaneous fat thickness in the study group was lower than that in the reference group (P <0.05). The operation time and ecchymosis regression time in the study group were both shorter than those in the reference group (P <0.05). The improvement rate of fat accumulation in the study group (96.97%) was higher than that in the reference group (75.76%) (P <0.05). The aesthetic satisfaction rate in the study group was higher than that in the reference group (P <0.05). The incidence of complications in the study group (3.03%) was lower than that in the reference group (21.21%) (P <0.05). Conclusion The application of cavitron ultrasonic surgical aspirator in the treatment of patients with fat accumulation in the nape and upper back can reduce their subcutaneous fat thickness, shorten the operation time and ecchymosis regression time, increase the improvement rate of fat accumulation and the aesthetic satisfaction rate, and reduce the incidence of complications, which is worthy of clinical application.