After loess is contaminated, the composition and internal structure of the soil will change, so that the tensile strength of the soil will also change. Based on this, in this paper, four kinds of polluted liquids with different molar concentrations of hydrochloric acid, sulfuric acid and nitric acid were manually configured, and the direct tensile failure test was carried out by comparing distilled water and contaminated soil samples, and discussed the tensile stress-tensile strain characteristics and process of acid contaminated loess. The effects of different acid solution types and concentrations on the evolution of soil tensile strength were further analyzed. The results show that the tensile strength of loess is lower than that of the unpolluted state with the invasion of the acid polluted liquid. With the increase of the concentration of the contaminated solution, the tensile strength of the loess polluted by hydrochloric acid and nitric acid were decreased, while that of sulfuric acid gradually recovered.The fitted concentration of the contaminated solution showed a good power function relationship with the tensile strength. Finally, based on the tensile strength and shear strength of the polluted loess, the fitting relationship of the combined shear strength of contaminated loess was discussed.