The invention discloses a ball grinding mill grinding aid for cement powder grinding and a preparation method thereof. The grinding aid is prepared from the following raw materials in parts by weight:10 to 20 parts of polymeric polylol, 4 to 7 parts of allyl methacrylate, 8 to 13 parts of ethanol amine, 4 to 6 parts of calcium lignosulphonate, 6 to 9 parts of polypropylene fiber, 5 to 8 parts ofturf, 12 to 16 parts of starch, 5 to 7 parts of phosphorus ore, 12 to 18 parts of silicon dioxide, 3 to 5 parts of 3-methyl-2-(n-methylamino)pentane, 5 to 7 parts of calcium formate and 100 to 150 parts of water. The prepared grinding aid is used for cement powder grinding in a ball grinding mill; the energy consumption can be reduced; the early strength of the cement can be improved; the powder grinding efficiency of the ball grinding mill is improved. In addition, the grinding aid provided by the invention is nontoxic and achieves the green and environment-friendly effects; no chloride ion ingredients are contained; no corrosion exists; no harm is caused on human bodies, buildings and the like; no environment pollution problem exists.