This paper studied the key factors influencing consumer purchase decision on infant milk powders under the context of e-commerce. In recent years there have been several scandals exposed about Chinese milk powders, causing major concerns among consumers and scholars. Meanwhile, e-commerce is fast developing in China, this study is aimed to understand what are the key factors influencing the consumer purchase intention in e-commerce and the correlations between the key variables. We first interviewed 30 parents (having kids 0-3 years old) and found that the following factors influence consumer purchase decisions: familiarity, trust and satisfaction. We then tested the relations among these factors with purchase intention with questionnaires. The study extended the theoretical framework on Trust, trust tendency, satisfaction, familiarity and their effects on Purchase intention, and also provided some guidance to the business managers on effectively communication in e-commerce to promote business.