Abstract: The corrosion compatibility of aluminum alloy and stainless steel,the main metal materials in the cooling system,was studied.The corrosion of coolant to aluminum alloy and stainless steel materials was observed by building laboratory simulation cooling system.The elemental composition of corrosion products was analyzed by EDS.The anion content in the coolant was detected and analyzed by IC.The electrochemical properties of aluminum alloy and stainless steel were tested.The results show that coolant with high anion content causes serious corrosion to aluminum alloy.Anodized 5A05 aluminum alloy and pickling passivation 022Cr17Ni12Mo2 stainless steel exhibit excellent corrosion resistance in coolant.The I_corrof anodized 5A05 aluminum alloy is 3.00×10^-7A·cm^-2.The I_corrof pickling passivation 022Cr17Ni12Mo2 stainless steel is 2.21×10^-7A·cm^-2.