Abstract: Changes of physical and chemical characteristics of magnetized water is introduced.Magnetic water′s application in agriculture had been introduced separately from magnetized water′s irrigation could promote seed germination and seedling growth，improve the production，reduce soil salinity，and enhance the utilization efficiency of water in irrigation，etc.In the point of the molecular group size′s view，principle of magnetic water′s function was analyzed，at the same time，made a comparative analysis of all kinds of magnetized way.Finally，application prospect of magnetized water treatment technology was introduced.