A mobile radiography system is disclosed, which includes a radiation source for radiating a plurality of beams； a detector for detecting the plurality of beams from the radiation source； a controller for determining an angular difference between the radiation source and the detector； and a positioning device mounted with the radiation source for recognizing a position of the detector relative to the radiation source based on the angular difference between the radiation source and the detector to align the radiation source to the detector. A method of aligning a mobile radiography system including a radiation source and a detector is also disclosed.
