An ultrasonic probe positioning method includes acquiring a first positioning location inside the ultrasonic probe, acquiring a first foot of perpendicular location corresponding to the first positioning location on an image marginal line with a detecting depth of the ultrasonic probe, setting a first center location within a detecting coverage of the ultrasonic probe, acquiring a second foot of perpendicular location, a normal plane vector, and a plane equation corresponding to the normal plane vector of the ultrasonic probe after the ultrasonic probe is shifted with an offset and rotated with a rotating angle, generating a second center location satisfying the plane equation according to the plane equation and the first center location, and optionally displaying a spherical space corresponding to the second center location on an ultrasonic slice image according to a distance between the first center location and the second center location.