Many markets are forecast to see significant changes due to the growth of electronic commerce made possible by the internet. The way of doing business with internet affects the market mechanism. It is now over 10 years since Malone et al(1987) set out their hypothesis on electronic markets, and electronic hierarchies. An electronic market is an interorganizational information system through which multiple buyers and sellers interact to accomplish one or more of the following market-making activities. And they predicted that markets evolve toward electronic markets, by reducing search cost, which may result in significantly. higher price competition among sellers and therefore lower prices for buyers. And the degree of two factors; asset specificity and uncertainty, affect the market mechanism. Products with low asset specificity and low uncertainty are compatible with a market relationship while the greater the asset specificity and uncertainty, the more likely it is to favour a hierarchical structure. Based on the these researches, we observed and analyzed a case study of market mechanism in Internet business. We found the fact that even though Internet could make the business environment in which lots of buyers and suppliers participate, electronic market will evolve market mechanism. 1 analyzed two factors, which affected market evolution. First, When Asset specificity is low in electronic commerce, market structure should be preferred to hierarchical structure. Second, When transaction uncertainty is low in electronic commerce, market structure should be preferred In hierarchical structure. This research covers conceptual and empirical aspects on electronic market structure. Future research should be variously done about the influential factors of electronic market mechanism.