本文通过对大渡河中游地区水环境的天然放射性状况的调查,得出大渡河中游地区的地表水环境放射性水平处于本底范围内,U含量在0.16μg·L~(-1)～2.98μg·L~(-1),Th在水中低于0.10μg·L~(-1),含量水平极低,Ra在0.005Bq·L~(-1)～0.028Bq·L~(-1)。通过底泥的分析,得出了3种天然核素在底泥中的分配系数,从分配系数可以分析出,在弯道出口水流较平缓的地方,天然核素较易富集在底泥中。 Based on the investigation of the natural radioactivity of water environment in the middle reach of Dadu River, the radioactivity of surface water environment in the middle reaches of Dadu River is within the range of the background, and the U content ranges from 0.16μg · L -1 to 2.98μg · L ~ (-1), Th was lower than 0.10μg · L -1 in water, and the content of Th was very low with Ra ranging from 0.005Bq · L -1 to 0.028Bq · L -1. Through the analysis of the sediment, the distribution coefficients of three kinds of natural radionuclides in the sediment are obtained. From the distribution coefficient, it can be concluded that the natural radionuclides are more likely to be enriched in the sediment .