The invention relates to a powder grinding aid suitable for kaolin, particularly relates to a powder grinding aid suitable for kaolin ultrafine powder, and belongs to the technical field of grinding of kaolin ultrafine powder. The powder grinding aid is prepared from the following substances in parts by weight: 1-5 parts of polymeric alkylol amine, 1-10 parts of polyethylene glycol, 5-15 parts of polyacrylamide, 1-15 parts of sodium pyrophosphate and 20-50 parts of wollastonite in powder. The grinding aid disclosed by the invention is compounded by mineral raw materials and common chemical materials, so that the powder grinding aid is sufficient in raw material source, available, low in toxicity, non-volatile, simple to produce and process, and low in cost; a kaolin grinding production enterprise utilizes the powder grinding aid disclosed by the invention; and the operation is simple and convenient. According to the powder grinding aid disclosed by the invention, the grinding efficiency is improved; the energy consumption is reduced; the surface energy of the kaolin ultrafine powder can also be effectively lowered; particle aggregation is avoided; the fineness of the power grinding aid is improved; the liquidity of the powder grinding aid is improved; and the whiteness of kaolin is not affected.