The invention discloses a water quality softening ball for reducing hardness of hardwater with high concentration of calcium and magnesium ions, which is mainly composed of follwing materials in weight percentage content of natural zeolite 4.5 to 51.9%, disodium ethylene diamine tetraacetate 3.6 to 48.5%, sodium carbonate 2.3 to 26.7%, sodium tetraborate 4.9 to 55.7%, sodium percarbonate 2.5 to 35.5%, epoxy adhesives 2.6 to 35.5%, epoxy curing agent 2.6 to 35.5%. The invention also discloses prepartion method of water quality softening ball. The water quality softening ball according to the invention can be repeated for many times, which is safe and non-toxic, and has good water softening effect, dosage of detergent is reduced, washing effects of detergent is improved obviously, no pollution and convenient application.