Background and aim: Information seeking behaviors are reflection of users' needs that Identifying and correct understanding them is very important in studies of information seeking. It is helpful in providing useful services to users. Experts have presented models based on cognitive, Process-oriented, and user-oriented approaches to better understand the different behaviors of searchers in information seeking. The purpose of all these models is to describe and explain the conditions that predict people's actions to find kind of information. Considering the different understanding of information behavior, the present study was performed with the aim that Bystrom and Jarvelin's model emphasizes on which concept of this field. Also, this Landscape to what extent has capability of Criticism. Method: In the present study, the Bystrom and Jarvelin's Information Seeking Behavior Model has been studied and analyzed using the library method. Findings: The findings showed that the task complexity, uncertainty, and ambiguity of concepts were related together. So, it can establish a clear place in the establishment of models. With the task complexity, the need for kinds of information such as informed people increases; therefore, the location of resources is important. Also, as complexity increases, more resources and more time are required to perform the search. Conclusion: The task complexity is an important variable in the information seeking process. Also, it affects on the need for kind of information, number of resources, and location of resources. It determines what kind of information is needed and what resources are used. It is associated with increase in the use of information of people as sources of information. Thus, information systems that facilitate information counseling of individuals; they are effective in this field and can be considered as supplement sources of information. Therefore, it is appropriate to focus more on this aspect of information resources in information systems. Since the task complexity has played a key role in the Bystrom and Jarvelin's Model; therefore, this concept can be placed next to situational, personal, and organizational factors and be considered as one of the important factors in the information search. It will be a suitable criterion for this model.