NOVELTY - Waste batteries are collected, ground and sorted by screening method, magnetic separation method and water flotation method to obtain metals and non-metals. The metals and non-metals are processed in reaction kettle at preset temperature and pressure to produce soluble materials and metal salt. The obtained compounds are polymerized by heating and pressurizing in the presence of catalyst to produce macromolecular polymers. The polymers are mixed to obtain T liquid flocculating agent and N liquid flocculating agent, and sewage treating agent is produced.    USE - Method for producing sewage treating agent from waste battery.    ADVANTAGE - The sewage treating agent is efficiently and economically produced without affecting the environment.    DETAILED DESCRIPTION - Waste batteries are collected, ground and sorted by screening method, magnetic separation method and water flotation method to obtain metals comprising copper, iron, zinc, nickel and aluminum, and non-metals comprising carbon rod, ammonium chloride, zinc chloride, graphite, acetylene black, paste, paper, plastic, bitumen, magnesium dioxide and manganese sesquioxide. Magnesium dioxide and manganese sesquioxide are added to a reaction kettle, and water is added. The reaction kettle is heated at 180-240 degrees C, pressurized to 1.5-2 atmospheres and acid is added to produce soluble material (A). Ammonium chloride, zinc chloride, paste and paper are added to the reaction kettle, water is added, heated to 180-240 degrees C and pressurized to 1.5-2 atmosphere. Alkali or acid is added to produce soluble material (B). Copper, iron, zinc, nickel and aluminum are added to a reaction kettle, and water is added. The solution is heated to 180-240 degrees C, pressurized to 1.5-2 atmosphere, and acid is added to produce metal salt (C). The compounds (A-C) are added to a polymerization device, heated to 70-100 degrees C, pressurized to 1-5 atmospheres, and catalyst is added to obtain macromolecular polymers (D1-D3), respectively. The polymer (D1) (80 parts weight) and polymer (D3) (20 parts weight) are mixed to obtain T liquid flocculating agent and N liquid flocculating agent, and sewage treating agent is produced. The catalyst is persulfate and bituminous coal. The total weight of persulfate is 0.1-0.2 times of the total weight of the waste battery. The total weight of the bituminous coal is 0.5-0.6 times of total weight of the waste battery.