An automatic collimator adjustment device (200, 200a, 200b, 200c) and method for medical treatment equipment (100) are disclosed. The medical treatment equipment (100) includes an automatic collimator adjustment device (200, 200a, 200b, 200c), which includes a processor unit (5), a depth camera (6), and a collimator control device (9). The processor unit (5) receives an instant image pixel depth signal (S11) acquired by the depth camera (6) to compare with a predetermined image pixel depth signal (S 13) of a predetermined human body portion (41) of a target human body (4) in order to generate at least one collimator adjustment signal (S2) to the collimator control device (9), so that the collimator control device (9) controls the collimator (2) to adjust the X-ray beam (11) to align with the predetermined human body portion (41) of the target human body (4).
