Abstract: Cyazofamid-pyraclostrobin(12.5%) oil dispersion was prepared by using methyloleate as the dispersing medium. The influence of adding hydrogenated rosin glycerin ester(HRGE),hydrogenated rosin pentaerythritol ester(HRPE) and rosin modified 4-tert-octylphenol resin(RMOR) on the physical stability and rheological behavior of the oil dispersion were investigated,respectively. The results of Fourier transform infrared spectroscopy(FTIR) indicated that the absorption peak of HRGE,HRPE and RMOR disappeared,meanwhile,the absorption peak of ester group was observed compared with rosin. This indicates that the softening point of different resin increases with the extension of carbon chain in their molecular structures.Moreover,the viscosity and the physical stability of the oil dispersion increase(lower oil separation ratio) with the increasing mass fraction of resin. The rheological tests show that the positive thixotropy is observed for the oil suspension prepared with modified resin. However,the oil suspension prepared with different resins significantly differs in the yield value,presented as RMOR >HRPE >HRGE >RA. The physical stability of different oil suspensions exhibits the same tendency. In conclusion,modified resins are capable of serving as the anti-settling agents in the preparation of oil dispersion of pesticides.