objective To explore the clinical and pathological features of cotyledonoid dissecting leiomyoma of the uterus with intravascular growth. Method 1 cases of cotyledonoid dissecting leiomyoma of the uterus with intravascular growth was observed pathological feature ,immunohistochemical stained and reviewed related literature. Results uterine muscle layers 15cmx13cmx10cm mass was detected with medical ultrasound in a 42-year-old woman and clinical diagnosis of uterine sarcoma. The naked eye uterine muscle layers in a haphazard mass and serous membrane outer protrusions like placental villi-like appearance were discovered, which was composed of well-differentiated tumors of smooth muscle cell and the distribution of the plexiform vascular with prominent hydropic degeneration. In myometrium at the same time form of venous blood tube has good smooth muscle hyperplasia, did not see beyond the blood vessels. The patient underwent total hysterectomy and the right Ssalpingectomy, no recurrence was found during the follow-up of 6 mouths. Conclusion cotyledonoid dissecting leiomyoma of the uterus with intravascular growth, also known as cotyledonoid hydropic intravenous leiomyomatosis(CHIL), is a very uncommon type of a benign uterine smooth-muscle tumor and the prognosis is good. The worrying appearance of the gross specimen is often mistaken for malignant or non-uterine lesions that may result in overtreatment. It is important to be aware of this entity to prevent overly aggressive treatment for this benign smooth-muscle neoplasm.