The invention provides a degradable magnesium alloy formed blank, preparation equipment and a preparation method thereof and a pressurizing screw prepared from the formed blank. The degradable magnesium alloy formed blank is prepared from the following components in percent by weight based on the total weight of the formed blank: 0.6-4% of Zn, 0.01-2% of Ca (the total weight of Zn and Ca is smaller than 5%) and the balance Mg and inevitable impurities, wherein the other impurity elements account for being smaller than or equal to 0.01% by mass, the tensile strength of the formed blank is not smaller than 400 MPa, the yield strength is not smaller than 320 MPa and the ductility is greater than 10%. The degradable magnesium alloy formed blank has excellent tensile strength and yield strength. The preparation method can refine grains, homogenize textures and improve the strength of a rod, and the pressurizing screw prepared from the formed blank has high strength and can be applied to wider fields.