To solve the problem of magnet installation and membrane placement,the magnetic field of magnetic filter was mainly analyzed.Firstly,ANSYS workbench was used to analyze the magnetic induction intensity on sedimentary surface by changing the relative position and direction of magnetic pole of two magnet piece.The result shows that,the magnetic induction intensity is stronger while the magnets attract each other than magnets repel each other on the sedimentary surface.The closer two parallel magnet pieces are,the stronger the magnetic field is formed on the sedimentary surface which is parallel with the magnetic field direction.On the basis of analysis by workbench,APDL module was used to simulate the magnetic induction intensity of the two magnet pieces.The result shows that,there is a blind area at the center of the two magnetic pieces.By using the method of mapping path,it is found that the maximum magnetic induction intensity is appeared at the plane 2 mm above the magnet pieces,where is the best position for filter membrane.