The organizational structure is the basis for the organization's leadership in achieving the goals and main strategies. By studying the features that require organizational structure in a project-based organization it is possible to find out the necessary solutions for the organization's managers to form the proper structure. The purpose of this research and writing of the article is to search and present the features of organizational structures in project-based organizations and tools are available to managers to match the organizational structure with the requirements of project-based organizations. In this article, first, some of the definitions presented in the organizational structure have been addressed and trying to provide an appropriate definition of organizational structure then, the history and ways of forming the classic organizational structures are presented. The new managers' attitude is related to organizational structures and some types of modern organizational structures are mentioned. Ultimately, a set of conclusions about the organizational structure shaping solutions tailored to the needs of project-based organizations which includes features of organizational structure in project-based organizations and some management tools are used to form an appropriate organizational structure in project-based organizations will be presented.
