Water softening is the use of ion exchange resin reduces or nearly all removed water calcium and magnesium ion content and to reduce water hardness and prevent scale deposition method. When the resin is adsorbed to a certain amount of calcium and magnesium ions must be regenerated. The resin was washed with saturated brine in the calcium and magnesium ions displace restore the softening resin exchange capacity, and waste discharge. Resin application areas: demineralized water use: process water, cooling water, boiler, steel smelting industry, chemical and pharmaceutical industries; system water time: Intermittent water / continuous water-hour water, the maximum water consumption; sources water sources, total hardness , turbidity and pollution index; cation exchange resin adsorption capacity of different cation exchange resin adsorption capacity of the different cations was in the order of cation exchange resin present in the solution adsorption capacity of the different cations are different, in general, the high ion adsorption capacity than on low ion adsorption capacity; with divalent ions, ion adsorption capacity for large diameter greater than the diameter of small ion adsorption capacity. The common cation adsorption capacity was in the order as follows: Fe3 +> Al3 +> Pb2 +> Ca2 +> Mg2 +> K +> Na +> H + ion exchange resin may also be based on the matrix of the type into the styrene resin and the acrylic resin. The resin type of chemically reactive groups of the resin determine the characteristics and types. First, a cationic resin and divided into two categories anionic resins, they may be respectively the cation and anion in solution by ion exchange. Strong acid cation exchange resin is divided into two categories and weakly acidic, strongly alkaline anion resin is divided into two categories and weak alkaline (or re-separation of acid and alkaline in class).