After the 1990s, with the expansion of globalization and interdependence between countries, one of the key features in China's foreign policy has been the development of relations through economic diplomacy, with a focus on strategic cooperation. The present study, while analyzing and evaluating China's economic diplomacy through strategic cooperation, evaluating the various levels of China's strategic cooperation, and conducting a case study of this country's strategic cooperation with Iran within the framework of the 25-year agreement, seeks to answer the question of Why China pursue its economic expansion and development in the form of economic diplomacy through strategic cooperation? Relying on the descriptive-explanatory method and within the framework of a case study, The research hypothesis is articulated as follows: the various levels of strategic cooperation, while providing China with the opportunity to assess the economic and political capacities of the other party for long-term cooperation, cause that country to be defined and institutionalized in the long-term system of China's international political economy goals (promotion within the framework of international power and balance against the West) by creating interdependence with the target country. Accordingly, the findings of this research indicate that Beijing seeks to leverage strategic cooperation to achieve political weight commensurate with its economic weight. By pursuing various levels of strategic cooperation within the framework of interdependence, Beijing, in addition to utilizing Iran's economic and political capacities for long-term cooperation, has sought to benefit from Iran's position within the context of its international political economy goals by fostering interdependence.