The invention provides a scanning device of a medical detector and an automatic assembling and disassembling device for a medical rod source. By the aid of the scanning device and the automatic assembling and disassembling device, the assembling and disassembling efficiency and precision can be improved, and radiation damage caused by manual operation can be prevented. The automatic assembling and disassembling device comprises a screw which is parallel to the axial direction of the rod source and a nut base which is in threaded connection with the screw, the circumference of the nut base is fixed, and an electromagnet is arranged on the nut base, so that the rod source can be connected or separated through control of energization and deenergization of the electromagnet. When a rod is required to be fed, the electromagnet is energized or deenergized, the rod source is positioned by the electromagnet, then the screw is driven to rotate in a forward direction, and the nut base drives the electromagnet on the nut base and the rod source to move with the nut base along the axial direction of the screw, so that the rod source is pushed to move towards the detector and finally sent into the detector. By the aid of the structure, the automatic assembling and disassembling of the rod source is achieved, the radiation damage caused by manual operation is prevented, the operation precision is high, and the reliability of rod source installation is improved.