Abstract: The article systematically studied the primary elements distribution of different grades of stream sediments as well as the grain size and element content characteristics of aeolian loess. The REE partitioning method has confirmed the existence of aeolian loess in stream sediments, what's more, the involvement has disturbed the content of elements in the sediments, and the interference varies as the sample particle size changes. The study supply important gist for the method and technique of stream sediment measuring, and suggest that the best sample grade should be greater than 80 mesh to avoid the interference of aeolian loess.