Consumer Behavior in Electronic Market is one of the urgent issues to be investigated in MIS and Marketing areas. This study adopts the comparative approach to examine the consumer preference between the sales channels. Majority of the confirming dimension (MCD) decision strategy, which allows the consumer to consider the alternatives in pair, is used as the underlying concept of preference. The pair of alternative in this study is the choices of the Internet and the conventional stores. The study additionally proposes a new scale for measuring consumer's preference and behavior. The preference is categorized into attribute-based and attitudebased preference in the structural equation model. The relationship between the two preferences and consumer behavior are hypothesized and tested. The results of LISREL support the research hypothesis and the scale is validated. In addition, the result verifies the role of mediator of attitude-based preference in the relationship.