Abstract: The adsorption properties of naphthyl sulfonate formaldehyde condensation(NNO) dispersant on the surface of hexaflumuron,such as adsorbed amounts,adsorption state,ζ potential,adsorption force,the adsorption layer thickness,were studied with remnants of concentration,ζ potential instrument,IR and XPS(X-photoelectron spectroscopy) at laboratory conditions. The results showed that the saturated adsorption of NNO dispersant on the surface of hexaflumuron particles and ζ potential increased with dispersant molecular weight and the fitting Langmuir equilibrium constant k of the adsorption of NNO dispersant increased with the molecular weight. The adsorption state is shown to be a multipoint type,and the clear "red shift" phenomenon was found on the surface of hexaflumuron particles adsorbed NNO.Hydrogen bond is important force in the combination and the surface layer thickness of the adsorption is 5.97 nm.Electrostatic exclusion and stereo-hindrance effect produced on the surface of hexaflumuron particles absorbing NNO dispersant can maintain the stability of hexaflumuron SC system.