Abstract: The feasibility to prepare a novel pesticide formulation,micro-emulsifiable granule (MEG) was studied using triazophos as a tested pesticide.The appearance of MEG was granular,and the microemulsion was formed with the dilution of water.D50 of emulsion was as a dependent variable,the dosage of surfactants were as independent variables,and surfactants were screened using uniform design of experiment with mixtures and partial least squares regression.Proportional method and bisectional method were introduced to optimize the dosage of every surfactant.Rotary granulation was selected as granulation method of preparation.Triazophos 15 MEG was formulated using emulsifier 500 and emulsifier 602 which were obtained by screening test.The emulsion of triazophos 15 MEG was light blue and clear,migration velocity of dispersed phase particle was zero,and emulsion stability was qualified between 0-3 420 mg/L water hardness and 10-50 ℃ water temperature.The emulsion’ D50 was 54.2 nm,the particle size distribution was 15.7-122 nm,and accretion rate of particle size was 0.01%/min.The phase separation of emulsion has not happened after centrifugation (5 min at 10 730×g).The results showed that the emulsion of triazophos MEG was microemulsion and the formulation of MEG could be successfully prepared.