Abstract: The rheology of hexaflumuron in the form of aqueous suspension concentrate(SC) was studied by means of controlled stress rheometer,with the particular emphasis on the effects of polymer dispersant MOTAS (Styrene-acrylic acid random copolymer) mass concentrations,molecular mass and hexaflumuron mass concentrations.It was found that the rheological behavior of hexaflumuron SC,which contained MOTAS,coincided with the Herschel-Bulkley rheological model.For a hexaflumuron mass concentration of 20%,the SC was pseudoplastic fluid and the flow behavior index n ≤ 1.0 when the MOTAS mass fraction was less than 3.0%; the SC was bulging plastic fluid and the flow behavior index n ≥ 1.0 while the MOTAS mass fraction was more than 3.0%.The yield value τ_H of hexaflumuron SC was correlated with the relative mass fractions of MOTAS and hexaflumuron.Little MOTAS was adsorbed on the hexaflumuron granule surface in its concentration ≤ 2.5%,and the uncoverd granules were connected with each other in some structures,which resulted in the biggist τ_H.When MOTAS mass fraction was 3.0%,saturated adsorption was achieved on the granule surfaces.The excessive MOTAS connected with each other in some structures,which produced the biggist τ_H likewise.Between dispersant MOTAS molecular mass 10 000 and 30 000,with the increase of MOTAS molecular mass,the viscidity and yield value τ_H of hexaflumuron SC decreased,while the flow behavior index n increased slightly.The n values were all less than 1,and the property of "shear thinning" of the pseudo-plasticity was not changed.