Abstract: The microstructure of cyhalothrin microemulsion was studied by means of conductivity measurement, and pseudo ternary phase diagrams were presented. The formation mechanism of cyhalothrin microemulsion was studied, with particular emphasis on the effects of molar fraction of sodium dodecylbenzene sulfonate(SDBS), electrolyte mass concentration and tempreture on cyhalothrin microemulsion. It has been found that: ①with the increase of molar fraction of SDBS, the areas of BC and O/W type microemulsion region increased first and decreased afterwards, while the W/O type decreased first and increased afterwards; ②with the increase of electrolyte mass concentration, the areas of W/O , BC and O/W type microemulsion region all increased first and decreased afterwards; ③with the increase of tempreture, the areas of BC and O/W type microemulsion region decreased, while the W/O type increased.

Key words: Cyhalothrin, Microemulsion, Phase diagram