A system for tracking objects such as a printed circuit board (PCB) undergoing multiple manufacturing processes traceability system includes a coding unit, a scanning unit, and a reading unit and a database. The printed circuit board includes at least two inner copper foil substrates, subsequent substrates can be added. The coding unit marks identification and manufacturing stage codes on the inner copper foil substrate for through scanning by the scanning unit emitting X-rays. The reading unit can receive and parse the codes identified by the X-rays, and determine the previous or a next stage according to a predetermined encoding rule without risk of stage repetition or stage omission or product misplacement. The database stores standard identities and information as to manufacturing stages as a reference.