The use of anionic polyelectrolytes is great technological importance to control the stability and flocculation behavior of colloidal suspensions. They are widely used in various industrial products, such as paints, coatings, ceramics, pesticides, pharmaceuticals, cosmetics, and drilling fluids, to modify the rheology and control the stability of the systems.In this investigate, rheological measurements obtained by a coaxial cylinder viscometer (shear rate

from 0 to 700 s-1), were carried to highlight the effect of two anionic polyelectrolytes such as, xanthan gum and sodium carboxymethylcellulose (Na-CMC) on the rheological properties of the bentonite suspension. Firstly, Herschel-Bulkley model was used for the flow curves of studied bentonite suspension whose the concentration in solid varies between 3-6%, the regression coefficient > 0.997 for all studied system. Secondly, electrokinetic measurements on all studied suspensions were also carried. Finaly, to asses the influence of polyelectrolytes on bentonite suspension, the rheological tests have been carried out on the polyelectrolytes solutions in absence of bentonite. The rheological behavior of xanthan solutions is shear-thinning non-Newtonian viscosity with yield stress. The obtained results showed that the yield stress and the consistency index increase with increasing bentonite concentration, on the other hand the flow index values decrease. It can be explained that the bentonite has a microscopic structure in platelets. It was noted also, the yield stress observed on rheograms is due to the internal fluid structure that forms at rest between the platelets. In the absence of flow, the platelets form rigid aggregates that are resistant to a certain value. from this yield , the structure is destroyed and the wafers are aligned with the flow. Also, the obtained results of the electrokinetic study, have showed an increase of the zeta potential of CMC and xanthan dispersions when the concentration of polymer in solution increases