Consumer trust in online transactions significantly is more important than in traditional markets, and Lack of trust in e-commerce component is considered as one of the main reasons for crashing some dot-com companies. The aim of present study is to examine factors that affecting the formation trust and their impact on purchase behavior in decision making process. This research is based on data that obtained through a survey study. In this study, the hypotheses were presented considering the variables were associated with trust and technology acceptance and diffusion model that in 2009 by Yu and Tao was presented. In this regard, factors were considered in the overall format of the trustee, trustor and environmental factors in the three-step approach to building trust, purchase and purchase repeat. Hypotheses were tested by Spss software and finally became clear that some of the factors have the strong impact on which level of customer behavior.