Background: Lemongrass contains essential oils with components of geraniol (20-40%), citronellal (25-50%), and citronellol (10-15) which cause aroma, so it can be used as a repellent. Essential oils of citronella can be developed repellent lotion to maintain stability of citronella oil in the form of lotion,then it takesformula lotion repellent the right Methods: citronella essential oilpreparations made lotion andin the physical properties of the test preparations. Then the optimization of stearic acid and TEA using themethod simplex lattice design on Design Expert software version 11. Results: The optimum formula was obtained, namely stearic acid of 18% and TEA of 2% with the optimum response of pH 5.58 and viscosity of 600.7 cps producing a value of desirability 0.917. Conclusion: All tests of physical properties of the preparation such as pH and viscosity met the requirements well and showed significant or no significant differences between the response predicted by the software and the response generated in the experiment. Verification to ensure that optimization with the software is acceptable.