Vesicle is one of molecular aggregates of surfactants consisting of one or more bilayers and its structure is usually spherical types. It is characterized by three factors such as structure(or size), surface charge and stability. Our reserch focuses on the spontaneous vesicle formation and these factors in the systems of cationic and anionic surfactants mixed aqueous solutions. We choose the cationic surfactant octadecyl trimethyl ammonium chloride (OTAC) which are widely applied to cosmetics and toiletries and the anionic surfactant ammonium dodecyl sulfate (ADS) that is less hydrolyzed in acidic solutions and less skin-irritative than sodium docecyl sulfate (SDS). In our systems, the structure is spherical and its size range from 250 to 400 nm by negative-staining TEM. The surface change is described by measuring the zeta-potential values which is positive at OTAC rich regions and negative at ADS rich regions. Finally, vesicle stability was examined through the adsorbance by the UV spectroscopy, our results are little changeable in adsorbance during two months.