In this paper, a new physical method for wastewater treatment that uses magnetic micro beads and a magnetic field is proposed. An experimental jar test for the separation of micro particle is carried out to show its feasibility. In the stirring process, contaminants of wastewater can adhere to magnetic beads, and then magnetic floc can be formed around the beads. This magnetic floc can be separated from the wastewater by an external magnetic field. A separation system is also designed, and its performance is numerically analyzed using the electromagnetic finite element method coupled with the fluid equation and the dynamic equation of particles wherein the driving force includes the magnetophoretic force, gravity, buoyancy, and drag force.