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.超音波探頭的定位方法包含設定位於超音波探頭內的第一定位點，取得位於超音波探頭之偵測深度之影像邊界線上，與第一定位點對應的第一垂足點，設定位於超音波探頭之偵測範圍內之第一中心點，當超音波探頭以一個偏移量移動及一個旋轉角度轉動後，取得超音波探頭的第二垂足點、平面法向量以及平面法向量對應的平面方程式，依據平面方程式及第一中心點，產生滿足平面方程式的第二中心點，及依據第一中心點與第二中心點的距離，選擇性地顯示第二中心點對應的球狀空間於超音波切面影像上。
