In this paper, through the preliminary exploration of the process of the magnetic field generated by the energized solenoid to push the magnet to move, a non-disassembly cleaning method suitable for the instrument in which the components inside the closed cavity are arranged in parallel along the axis is proposed and a basic cleaning method based on this method is made. In the device model, the effective magnetic circuit length of the coil is reduced by adjusting the magnetic gap distance, and the remote control function is added to realize the non-dismountable cleaning of the inside of the closed reactor.