Objectives. To present the details of trophoblastic diseases and advanced ultrasound diagnoses including color/power three dimensional (3D) and four dimensional (4D) ultrasound. Methods. Details of classification, clinical course, pathological change, diagnosis and chemotherapy were studied. Ultrasound diagnosis with real-time B-mode, transvaginal scan, 3D image, color/power Doppler flow mapping, 4D moving image and pulsed Doppler flow velocity wave were analyzed in hydatidiform mole and choriocarcinoma. Effective primary chemotherapy as well as prevention of choriocarcinoma were proposed in the treatment of trophoblastic disease. Results. Three D and 4D color/power Doppler discovered a characteristic blood flow pattern and its motion image as an effective new diagnostic modality for the total hydatidiform mole. Invasive mole and choriocarcinoma were differentiated by real-time B-mode and color Doppler ultrasound detecting villous pattern surrounded by color flow image in the invasive mole. Chemotherpeutic sensitivity can be estimated at a very early stage by the sudden increase of peripheral blood flow impedance. The diagnosis of hydatidiform mole in its earliest stage of development was emphasized in the ultrasound study. Conclusion. New ultrasonic diagnosis was 3D and 4D color/power flow imaging, particularly for total hydatidiform mole. Color/power Doppler flow mapping was used not only in the diagnosis but also for the monitoring of chemotherapy of trophoblastic neoplasia.