The invention relates to a preparation method of ternary system material, in particular to a preparation method of lithium cobalt nickel manganese oxide ternary system material for lithium ion batteries. The invention applies ensured ternary system material salt as raw material. After needed matching weight, by means of eve dissolving and mixing, a composite metal oxide prepared by a spray-roasting method is used as a fore body. The fore body is mixed with a lithium-source compound according to the substance amount of 1:1-1.5, and then roasting is carried out at the temperature of 700 to 1000 degrees centigrade to obtain the ternary system material. The tail gases, such as vapor, acidic gas, generated in the spray-roasting process are absorbed by a washing tower to obtain acid. The invention has the advantages of advanced technique, stable production, low cost, no waste water discharge, environmental protection, high product purity, even granularity, high crystallinity, etc.