The invention discloses a regulation and preparation method of a LPSO phase in an Mg-Gd-Er-Zn-
Zr alloy, and belongs to the technical field of heat treatment. The Mg-Gd-Er-Zn-
Zr alloy is heated up to the medium temperature of 300-350 DEG C in a heat treatment furnace; the temperature is kept for 15-60 minutes; the
quenching is performed by hot water of 70 DEG C; then, the Mg-Gd-Er-Zn-
Zr alloy is heated up to the high temperature of 480-520 DEG C; the temperature is kept for 3-8 hours; the
quenching is performed by the hot water of 70 DEG C; and finally, the Mg-Gd-Er-Zn-Zr
alloy is heated up to the secondary-high temperature of 400-460 DEG C; the temperature is kept for 12-50 hours; and the
quenching is performed by the hot water of 70 DEG C. The method not only can control the
volume fraction and one-dimensional dimension of the LPSO phase in the
alloy, but also can effectively eliminate the component segregation of the
casting alloy. Through the control process, the
volume fraction of the LPSO phase is 3.2-45.67%, the range of the one-dimensional dimension is 25-120 microns, the component segregation and thick primary tissues of the
casting alloy can be obviously eliminated, and the mechanical performance of the alloy is obviously improved.