Abstract: The microstructure and mechanical properties of AZ91B magnesium alloy under different current were tested by adding TiB₂ particles as reinforcement and solidification treatment by electromagnetic stirring. The results show that the electromagnetic stirring does not change the phase composition of the alloy. Under electromagnetic stirring, a lot of thick polygon TiB₂ particles are formed, and a large degree of agglomeration occurs. More small-size particles are obtained by increasing the current. The low hardness zone is located at the lower part, which is generally in the range of 64-67 HV. The hardness of the higher parts also increases obviously, and the hardness of the top reaches a higher value of 68-70 HV.Electromagnetic stirring effectively reduces the hardness difference of different heights. The yield strength and fracture strain properties of the alloy can be improved after electromagnetic stirring. With the increase of electromagnetic stirring current, the strength increases first and then decreases, and the maximum value occurs at the current of 200 A, when the tensile strength is 262 MPa and yield strength is 182 MPa.