The invention relates to a dynamic shielding system, which comprises a shielding body with a through hole, a base seat provided with a linear expansion power source, a rotating ring which is arranged on the base seat and can be pushed forward by the linear expansion power source to rotate, and two or more than two pieces of shielding plates which can shied the through hole arranged at the lower part of the shield body; wherein the external section of one side of the shielding plate is provided with a rotating hole and a slotted hole; the rotating hole is sleeved on a locating column which is arranged on the base seat and the slotted hole is sleeved on a driving lever which is arranged on the rotating ring; the linear expansion power source is arranged on the base seat which is same to thetangential direction of the through hole of the shield body, a linear push rod at the top thereof is contacted with a supporting arm which is transversely arranged, one end of which is fixedly positioned and the other end tightly abuts a fluctuant column arranged on the rotating ring; the supporting arm drives a connection rod of the rotating ring and moves together; the two or more than two shielding plate which can shied the through hole arranged at the lower part of the shield body encircle the centre to revolve together, and the drawing rod causes the shield plate to revolve on the axis of the drawing rod. The system is characterized by reasonable and compact structure, convenient and reliable usage, effective shielding, associative perception, etc.