We have studied the emulsion particle size change, the stability, and the possibility for applications of cosmetics depending on the concentration and variety of phosphatidyl choline (PC). The relationship between the emulsion particle size and the concentration of PC was checked using lecithin that included either 39% or 70% PC. The greater PC concentration gave the smaller particle size because of the critical packing parameter (CPP) of each lecithin. The cell toxicity of lecithin is similar to that of nonionic surfactants, and so it could be used as a skin-compatible material in cosmetics that use its benefits. PC, the main ingredient of lecithin, forms stable vesicles because its CPP is 1/2 ~ 1. Single-chain surfactants resulted in smaller particle when used with lecithin; Tween 60 made the smallest particles, so we believe its CPP is similar to that of PC. The particle size of a sample over the phase inversion temperature was smaller than one below it. In a study of emulsions using oils of different densities, silicone oil (the highest density) was worked positively in emulsion particles. The moisturizing effect of an emulsion using lecithin was better than that of an emulsion using nonionic surfactant. Finally, we prepared emulsions using unsaturated lecithin and saturated lecithin at the same concentration and found that unsaturated lecithin creates smaller particles.