Objective Cotyledonoid dissecting leiomyomawas a rare type of uterus tumors. Because of the lack of knowledge about the ultrasonic patterns of this kind of disease, misdiagnosis frequently happens. Reviewing the cases and relevant researches was helpful to understand the disease and figure it out in ultrasonic images. Methods Six cases of patients with dissecting leiomyoma were reviewed which were hospitalized in Beijing Obstetrics and cotyledonoid Gynecology Hospitalduring 2011 to 2016. All of the patients underwent ultrasound examinations before surgery. The ultrasound findings, clinical presentations and pathological features of the 6 patients were evaluated. Results In 6 patients with CDL, 5 cases were typical intramural dissecting leiomyomas, the inhomogeneous solid masshad irregular boundaries with muscle, color Doppler revealed intenseblood flow signals in the mass. One case exophytic component was in continuity with a lobulated, multinodular myometrial tumor with an irregular border, resembling cotyledon of the placenta. Conclusions Cotyledonoid dissecting leiomyoma was found to be inhomogeneous solid masswith irregular boundariesin some cases, exophytic component was multinodular myometrial tumor, resembling cotyledon of the placenta. Due to bizarre, sarcoma-like gross appearances. Thusit is hard to be diagnosed before surgery by ultrasonography, this type of lesion should be subjected tocareful ultrasonic examination in order to avoid over treatmentand preserve the fertility in young women.