An ultrasonic device and a method and system for transforming the display of a three-dimensional ultrasonic image thereof. The method comprises: first acquiring original ultrasonic three-dimensional body data including a tested object (S10); detecting the orientation of the tested object from the original ultrasonic three-dimensional body data according to image features of the tested object (S20); then comparing the orientation of the tested object with a desired orientation, so as to obtain a rotation transformation parameter in a three-dimensional coordinate system (S30); next, rotating and transforming the original ultrasonic three-dimensional body data according to the rotation transformation parameter, so as to obtain the transformed three-dimensional body data (S40); and finally, outputting the transformed three-dimensional body data (S50). Therefore, the ultrasonic three-dimensional body data of the tested object can automatically rotate to the desired orientation without requiring manual adjustment, thereby improving the efficiency thereof.