The invention provides an additive for preparing suede on a monocrystalline silicon chip, which comprises: polyethylene glycol, sodium benzoate, citric acid, hydrolytic polymaleic anhydride, sodium acetate and water. The invention also provides a suede preparation liquid for preparing suede on a monocrystalline silicon chip, which contains the foregoing additive for preparing suede on a monocrystalline silicon chip and an aqueous alkali in a mass ratio of 0.2-5:100, wherein the aqueous alkali is the aqueous solution of an inorganic or organic alkali. The invention also provides a method for preparing suede on a monocrystalline silicon chip, by using which suede can be prepared on the surface of a monocrystalline silicon chip with the foregoing suede preparation liquid. When used to prepare suede on a monocrystalline silicon chip, the additive can form uniform, tiny and dense suede pyramids without using a lot of isopropyl alcohol or ethanol, thus greatly reducing the chemical oxygen demand of the suede preparation liquid, and consequentially, the invention reduces suede preparation cost and environmental pollution and improves the technical stability of crystalline silicon solar cell and therefore has a good practical value.