Abstract: Metal parts usually prevent rust by means of nickel and chrome plating etc.，but due to cost and other factors， electroplating enterprises will generally try to reduce the thickness of the coating，cause plated parts′rust proof performance decrease，thereby anti rust agent is required to be coated to supplement the antirust performance.A low concentration environmental friendly aqueous rust inhibitor was prepared by taking the low concentration of lithium silicate solution as the main material，to mix with a variety of different types of auxiliary agents.Using the orthogonal method to optimize the process，and the optimum conditions were confirmed as follows: concentration of lithium silicate was 0.012 mol/L，addition amount of organic acid was 0.5 mL/L，addition amount of organic amine 0.2 g/L，amount of phosphate 0.15 g/L，and addition amount of OP-10 0.3 mL/L.Under the best proportion of conditions，aqueous protective fluids had good antirust performance，non-toxic，environmental friendly，and stable，and they still had well rust resistance after 60 d.

Key words: aqueous rust inhibitor, lithium silicate solution, organic acid