Abstract: Tag-guided image positioning method includes: defining a three-dimensional space coordinate system based on tag spatial position information obtained by identifying reference image(s) of a patient's body part disposed with reference tag(s), and position/direction data related to a medical device reference point (MDC)/direction (MDD); estimating a target coordinate in system representing a position of a target point based on three-dimensional medical image of patient's body part marked with target point and reference marker(s) corresponding to position(s) of reference tag(s) and reference coordinate(s) in system representing position(s) of reference tag(s); and outputting a positioning result as a basis for whether patient's body part should be adjusted based on a judgment result indicating whether or not in system a distance between target coordinate and a device coordinate representing a position of MDC and a pointing representing MDD are respectively consistent with a predetermined distance/medical device i