Abstract: Taking unclassified-tailings paste as the experimental slurry，the orthogonal design method is adopted to design the experimental scheme.And R/S+ SST rheometer is used to test the rheological characteristic of paste and investigate the effect rule of three factors on rheological parameters，which are weight concentration，cement-tailings ratio and slag-cement ratio.With the aid of the range analysis，the variance analysis and the multiple regression analysis methods，the experimental results showed that the relationship of between yield stress and weight concentration was appeared as an exponential increase function.The paste has the rheological characteristics of slurry，such as thixotropism and shear thinning.Among three factors of weight concentration，cement-tailings ratio and slag-cement ratio，their influence level is weight concentration＞slag-cement ratio＞cement-tailings ratio.There，weight concentration has a relatively significant effect on the rheological parameters. 

Key words: Vane rheometer, Orthogonal design, Unclassified-tailings paste, Rheological parameters