The invention discloses a blocking apparatus based on a particle flow blocker. The blocking apparatus comprises a blocker, a blocking block is arranged below the blocker, the apparatus also comprises an execution element and a position detecting element, the execution element comprises a solenoid valve and a cylinder, the solenoid valve is arranged at one end of the top of the blocker, the cylinder is arranged on the top surface of the blocker in a transverse manner, a movable end of a piston rod of the cylinder and the blocking block are fixedly connected through an outside rod stopping block, an inside rod stopping block, and an arm rod, the solenoid valve is connected with the cylinder, air enters the cylinder through control of compressed air so that reciprocating motion of the piston rod of the cylinder is realized, the position detecting element comprises a first limit switch and a second limit switch, and the first limit switch and the second limit switch are respectively arranged at two ends of the motion stroke of the piston rod. The invention also discloses a realization method of the particle flow blocking device with fast response. According to the device and the realization method, the cylinder is rapidly controlled to perform corresponding extending motions of the piston rod, the blocking block is driven to cut off beams in time, and the therapeutic safety is greatly improved.