A capturing device for magnetic impurities in liquid metal comprises a magnetic field system, a wire net, a crucible, a smelting tank, a sealing system, a fastening connecting rod, a support platform, a motor, a belt and a gas passageway; permanent magnets in the magnetic field system are placed in limit slide blocks on a guide rail and provide a magnetic field through a magnetic yoke; the crucible is arranged in the smelting tank as a liquid metal container; the wire net is vertically arranged in liquid metal through a rotating shaft; the sealing system comprises a sealing flange, the rotating shaft, a copper sleeve and a sealing oil trough; the position of the wire net in the liquid metal can be changed by adjusting the lifting height of the rotating shaft, and the fastening connecting rod is fixed through a fastening screw so as to fix the rotating shaft; the motor drives the rotating shaft through the belt; and the gas passageway is arranged at the upper end of the sealing oil trough and is used for allowing liquid metal protective gas to pass in and out. The capturing device for magnetic impurities can be used for simulating part of working parameters of magnetic traps in liquid metal and capturing magnetic impurities and is a simple and effective device for research on action of magnetic impurities in liquid metal.