The invention provides a pollution-free microcrystalline phosphating treatment solution for brake pad hardware, which is mainly made from the following raw materials in portion by weight: 40 to 50 portions of zinc nitrate, 22 to 30 portions of zinc dihydrogen phosphate, 30 to 40 portions of Mazhev salt (manganous dihydrogen phosphate), 1.5 to 2 portions of guanidine nitrate, 1.5 to 2 portions of sodium m-nitrobenzene sulfonate, 1 to 2 portions of sodium tripolyphosphate, 2 to 4 portions of tartaric acid, 2 to 3 portions of sulfosalicylic acid, 1.5 to 2.5 portions of citric acid and 1,000 to 1,200 portions of water. The solution is used for the blackening-phosphating treatment of the surface of iron hardware, and has the characteristics of fast phosphorization, good performances, little environmental pollution, low cost, etc. The treatment solution has the advantages of fine phosphatized crystals of phosphating films, uniform color in consistent black and good corrosion resistance. Especially, as the treatment solution chooses the raw materials with little environmental pollution and high efficiency, the treatment solution acquires excellent effects in both phosphatization and environmental protection through optimized combination and reasonable proportioning.