An intelligent virtual avatar is very useful in an e-business website, it can attract users to explore more business information, how to construct the architecture of an intelligent virtual avatar is a very important topic for a friendly interface of e-business. Based on current research on cognitive science, architecture of an intelligent virtual avatar is presented, and a computational cognitive model that integrates outer stimuli and inner mental variables (motivation, emotion, personality) is proposed, the result can support a quantitative method to control the behaviors of an intelligent virtual avatar.