Sustainable urban security is all-round security and monitors different dimensions. Meanwhile, one of the disturbing factors of the sustainable security of big cities, which is considered a serious threat in the field of realizing their sustainable security, is the problem of marginalization, which is the result of inappropriate social and economic planning. Today, sustainable security is accepted as the dominant aspect of security planning. The main emphasis of this approach, as a comprehensive and multifaceted approach, is to identify the factors disrupting security in the environment, surrounding conditions, and in the next step, developing practical programs to solve them.In this regard, due to the importance of the movement of megacities in the direction of sustainable security, which in a way guarantees their sustainable development, this research has been carried out using a descriptive method to collect information and using library and field methods. The results of the research show that the residents of marginal areas in Tehran metropolis feel relative deprivation due to the lack of necessary sustainable urban development (physical and physical, social and cultural, economic), which is a threat to the security of this city.And social damage as a factor threatening urban security is more prevalent in the suburbs of Tehran.