The invention discloses a bulb tube movement control unit used in a digital radiology photography system, comprising a bulb tube holding hoop, a bulb tube bracket and a horizontal rotating shaft which is arranged on the bulb tube bracket. The bulb tube holding hoop is fixedly connected with the horizontal rotating shaft; the bulb tube movement control unit also comprises a motor arranged on the bulb tube bracket; the motor is connected with the horizontal rotating shaft through an actuating mechanism; the motor drives the horizontal rotating shaft to rotate, thereby driving a bulb tube to rotate. The bulb tube movement control unit used in the digital radiology photography system drives a screw bevel gear mechanism through the motor arranged on the bulb tube bracket, realizes the automatic rotation of the bulb tube around the horizontal rotating shaft, and realizes the automatic tracking of the bulb tube rotating position through an encoder arranged on the bulb tube bracket; the relative position between a DR detector and the bulb tube does not need to be adjusted manually; therefore, the movement noise is eliminated, and the work intensity of doctors is reduced.