Abstract: The thixotropy of pastes is a complex rheology phenomenon,which concerns paste mixing preparation,pipeline transportation,flowing in stopes and many other aspects. But currently it is difficult to interpret many kinds of thixotropy-related phenomena in unclassified tailing paste technology due to the lack of a common understanding of its mechanism. To explain the thixotropic behavior of a unclassified tailing paste in the process of stirring,the impacts of unclassified tailing particle size,slurry concentration,addition of cement and standing time on the paste thixotropy were studied by conducting rheological experiments of the paste in different conditions of a certain mine,and the thixotropic behavior of the paste and its influence on the stability were analyzed. The results show that unclassified tailing particles disperse in the slurry in the form of three-dimensional network structure,and their thixotropy and yield stress are relevant to the stability of the slurry. Influenced by ultrafine composition,cement-tailing ratio and slurry concentration,the thixotrophic characteristics of the paste can be divided into two process,shear failure and standing recovery. Besides,the paste's rheology characteristics will change over time.