Abstract: The effects of the additives on the rheological behavior of the microalumina concentrated suspensions were studied. The result shows that, after adding the additive into the system, the behavior of the dilatant flow is enhanced. and the apparent viscosity, thixotropy and viscoelasticity of the suspension are improved. The dilatant will be weakened and the plastic properties will be increased. This will be beneficial to the improvement of working properties of the monolithic refractory composed mainly of microalumina powder.