Abstract: Using phase transfer method, the formulation of hexaconazole 50ME(O/W) was studied and appropriate solvent and emulsifier were selected. The best solvent were the mixture of cyclohexanone and N,N-dimethylformamide (3∶ 1, m/m), which was 20% weight of total composition; the emulsifier was the mixture of 1602#, EL-10 and 500# (2∶ 2∶ 1), occupied 20% weight, the other component was water. The main specifications of hexaconazole 50ME with water and different content of calcium ion for the physical and chemical stability were tested after storage under 0℃ and 54℃. All of them were up to grade and there was no significant difference with deionized water.