Abstract： Objective:To investigate the ultrasound features of malignant mixed mullerian tumor(MMMT)of the female re-productive system in order to improve the diagnosis of this disease.Methods:The clinical data and ultrasonic manifestations of 37 cases of MMMT diagnosed by pathology in the Third Affiliated Hospital of Zhengzhou University from January 2018 to July 2023 were retrospectively analyzed.The 37 patients were enrolled with an average age of 56 years.Thirty-two cases oc-curred in the uterus,4 cases in the cervix,and 1 case in the ovaries.Thirty-five cases had symptoms of vaginal bleeding or fluid flow,and 2 cases had symptoms of abdominal distension.Results:The serum CA125 was evaluatedin 32 women before operation,8 cases were higher than normal and the remaining 24 cases were normal.There was no significant positive corre-lation between CA125 level and tumor size and tumor staging.The characteristic features of MMMT color Doppler ultrasound in female reproductive system were as follows:single shot,loose echo;large in size,and the average length was 52 mm,of which 16 cases were larger than 80 mm.Infiltrating growth from the interior to the outside of organs,without clear capsule,but had the boundary with normal tissue.Loose heterogeneous low and medium echoes were interspersed,showing a"trabecu-lar pattern".When the lesions were large,a"fissure-like"anechoic area,and a"honeycomb"pattern of mixed distribution of low and high echoes in the central area could be seen.The peripheral blood supply of the tumor was abundant,while the central area of larger tumors had less blood supply.Conclusion:MMMT in female reproductive system often occurs in the uterus,and the symptoms are mostly vaginal bleeding and fluid flow in postmenopausal women.The color Doppler ultrasound manifestations of this disease are characteristic.The summary of the ultrasound images is beneficial for the early diagnosis of MMMT.