Abstract: To replace the common emulsifiers and solvents,the mix-emulsifier of benzyl starch ether in combination with alkyl polyglycoside and solvent of methyl oleate were used in preparation of 10% cyhalofopbutyl aqueous emulsions. The structure of benzyl starch ether was characterized by FTIR and UV spectroscopies in case of benzyl carboxymethy. The effects of different processing parameters,including the concentration of benzyl starch ether and alkyl polyglycoside in pretreatment fluid,rotation speed and shearing time on the stability of emulsion were studied by measuring oil droplet diameter distribution and using the orthogonal experimental design. The results demonstrate that benzyl starch ether compared with pristine starch has absorption peak of benzyl carboxymethyl. High stable emulsions can be prepared with benzyl starch ether and alkyl polyglycoside complex in 3:2 molar ratio as emulsifier and 9% methyl oleate as solvent. The mean droplet diameter of emulsions is about 1.02 μm and is increased by only 0.1~0.6 μm after storing at 25℃ for 6 months or at(54 ± 2)℃ for 14 days and the water separating proportion is only 2.7%. Cyhalofop-butyl oil-in-water emulsion prepared with benzyl starch ether,alkyl polyglycoside and methyl oleate has a better stability than the conventional emulsions.The results of this study show that benzyl starch compounding with alkyl polyglycosid and methyl oleate can be used as an alternative emulsifier and solvent for the environmentally friendly oil-in-water emulsion formulations.