An ultrasonic detection method and ultrasonic imaging system for a fetal heart. Since after three-dimensional volume data is obtained, at least one point within a fetal heart in the three-dimensional volume data is identified, the spatial position where a fetal heart cross-section is located in the three-dimensional volume data is identified according to the point, and the fetal heart cross-section is then extracted from the three-dimensional volume data according to the identified spatial position, the fetal heart cross-section can be quickly acquired from the three-dimensional volume data. The present invention is simple and easy to use, and is convenient for a doctor to make a diagnosis.
