Objective: To optimize formula of Yuhong nanoemulsion and provide a reference for improving of quality stability of this preparation. Method: When composition of nanoemulsion changed

conductivity change was observed on the basis of magnetic stirring at a constant temperature

quadratic regression model was adopted to determine critical points of phase transition

then formula of Yuhong nanoemulsion was optimized by making classic ternary phase diagram. Result: Optimum formula was as following:mixed emulsifier with hydrophilic-lipophilic balance value of 11.26

ratio of emulsifier and co-emulsifier 2.603:1

with mixture of glycerol-ethanol(3:1) as a co-emulsifier

refined sesame oil as oil phase

Wahaha purified water as water phase

oil phase-water phase-mixed emulsifier(28.99:63.74:7.27). Conclusion: This optimized formula is stable and feasible with higher drug-loading

it is suitable for improving stability of Yuhong ointments.