Today, several educational portals established by organizations to enhance web E-learning. Intelligence agent's usage is necessary to improve the system's quality and cover limitations such as face-to-face relation. In this research, after finding two main approaches in this field that are fundamental use of intelligent agents in systems design and focusing on human-based agents, second method selected and is designed and implemented in a simple way as an educational assistant to answer the students frequently asked questions. Consequently the efficiency of this method is evaluated by Expectancy confirmation-Information technology model. By examining the results of the students interacted with designed agent through the learning management system of Mehralborz institute, and the conceptual model based on e-learning effectiveness, ease of use, user satisfaction, and usefulness variables gained the scores of 55, 58 and 57 percent that represents the overall effectiveness factor is medium. Some applicative suggestions for developing intelligent agents as educational assistants are provided for virtual universities and e-learning portals.