Abstract: Abstract: The objective of this experiment is to select the basic formula of imidocarb dihydrochloride emulsion(W/O). Screening of the oil phase, the emulsifie species , the amount of emulsifie and the oil-water ratio by the univariate analysis, the optimum formulation and technology of imidocarb dihydrochloride emulsion(W/O) by means of orthogonal test; Basic Formula of imidocarb dihydrochloride emulsion(W/O) were determined, finally, it were screened out that white oil was the optimum oil phase, the optimum hydrophilic surfactant OP-10 was the optimum emulsifier, the Optimum Combination of white oil, the lipophilia surfactant Span-80 and the optimum hydrophilic surfactant OP-10 was preliminaryly ascertainmented. the optimum dosage of the emulsifier in the emulsion is 10% of the prescription , the optimum oil-water ratio was 7:3, the optimum formulation and technology was determined that the emulsifying temperature 50 ℃, emulsifying time 3 min, stirring speed 8000 r/min. through the obove formulation screening and the Process optimization, 2% imidocarb dihydrochloride emulsion(W/O) was prepared.