Finding the ideal location for your business is one of the most critical and important steps you will have to undertake. Otherwise, done in the wrong way you will only end up paying an expensive cost for an unsuitable location. Therefore to select the perfect location for your business, this study makes a reasonable and simple model for retail shops by calculating occupation population for each store applying Huffs "Probability Theory" to Hypermarket in Seoul. Then this study, based on occupation population, has divided every unit section (dong scale) into 4 market types which represent the state of the competitive markets, including monopoly, oligopoly, competitive, and noncompetitive markets. Consequently, the most reasonable place to locate a new store is where it can take most of the customers, that is, a place which can take non-competitive market as much as possible and is distant far enough from competitive market where competition is severe.