Different kinds of freshwater sediment quality guidelines (SQGs) have been developed using a variety of approaches. Comparisons of lower SQGs values, upper SQGs values and the gray zones of different contaminants have been made to find and evaluate the differences among various published SQGs. The results have shown that obvious quantitative differences varied from 2 to 15 times and 4 to 29 times respectively among those lower SQGs values and upper SQGs values, and all SQGs have wide gray zones which heavily influence their applicability. The differences mainly due to the complexity of controlling factors associated with the bioavailability of various contaminants, and the uncertainties of SQGs deriving approaches.