Solidified structure, crystal texture and mechanical properties of Mg97Y2Cu1 alloy reinforced by long period ordered structure under DC magnetic field(0~1.2T) were studied. The results show that primary grain size and content of Y in matrix of the alloy decrease with DC magnetic field treatment. With the increase of magnetic field strength, the plane texture enhances firstly, then weakens, and the turning point is 0.9T, the plane texture enhances gradually. The strength and elongation of the alloy increase gradually in general. When the magnetic field strength is 0.9T, comprehensive mechanical properties of the alloy are the best. Tensile strength and elongation of the alloy are increased by up to 96.6% and 61.1%, respectively, compared with the sample without treatment.