In knowledge-based economy, the intellectual capital is used for value creation in the organization, and in today\'s world, the success of any organization depends on its ability to manage these assets. In the ultra-competitive era, organizations are facing an environment characterized by increasing complexity, mobility and globalization. Therefore, to sustain, organizations are facing new challenges and releasing these challenges requires paying more attention to development and nurturing the inner skills and abilities. This is done through the basics of intellectual capital and knowledge assets which are used by organizations to reach a better performance in the business world. Knowledge and intellectual capital are recognized as a sustainable strategy to achieve and maintain the competitive advantage of organizations. Nowadays, because of the increasing importance of knowledge and intellectual capital in corporates sustainability and the unmatched role they play in maintaining the competitive position, several studies have addressed the intellectual capital and its components from different aspects. This study first specifies the history and the definition and components of intellectual capital, and then features of all components are discussed. In addition, the importance aspects of intellectual capital, the measurement objectives, as well as methods used for classification of intellectual capital measuring are also discussed and analyzed.