Abstract: In order to study the pollution characteristics and risk level of semi-volatile organic compounds (SVOCs) in water and surface sediments of Ulansuhai Nur, water and sediment samples from 7 sites were detected and analyzed. The total concentration of SVOCs in water and sedimentary species ranged from 449.7 to 691.0 ng/L and 144.4 to 587.5 µg/kg, respectively. Polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) were the main contaminant compounds found in all samples. Other SVOCs were not detected or only trace. PAHs pollution in water and sediment mainly came from petroleum source and mixed source of coal and biomass fuel combustion. PAEs pollution mainly came from plastics and chemical industry and domestic wastes. The ecological risk of the main contaminants in water and sediment of Ulansuhai Nur was at a low level in general, and the health risk also presented a low level in terms of drinking water and exposure.