Consumer decision behavior has been an interesting research topic for researchers and marketing people. While E-Commerce websites and online self-service are becoming more and more popular, it is important to understand how to support consumer in their online shopping decision process. The purpose of this research is to understand how consumer¡¦s decision behavior would be influenced in online shopping environment, when facing different product price and complexity, and discover the personal factors that might influence it¡¦s decision behavior. The result of our research showed that product complexity has significant influence on consumer¡¦s decision behavior. When product complexity become higher, the effort and time for a consumer to complete a purchase decision will also become higher. When consumer is more familiar with the product, more involve with the product, or have higher computer self-efficacy, consumer will use much harder decision tools then usual. But our result also showed that product price has no influence on consumer¡¦s decision behavior, this might be that in our experiment, consumers don¡¦t really have to pay for the product, so the influence of product price has no effect on consumer. From our result we can know that for different product complexity and consumer will result in different decision behavior. In the future, online shopping store can provide different decision tools for different consumer when facing different products, to help consumer make better decision.