The emergence of human and natural hazards on a global scale has led to a change in the discourses, themes and orientations of political-security research. The end of the Cold War marked the beginning of the development of new concepts in the field of security, which are based on cooperation and interaction between political units. The development of concepts of human security, environmental security, etc., has attracted the attention of many researchers, given the increasingly destructive role of man in the biosphere and its spatial consequences in the form of socio-political crises. It seems that the mainly unpleasant consequences arising from environmental degradation, global warming and climate change have had long-lasting effects on the livelihoods and sustainable security of individuals and communities throughout the biosphere, especially in developing countries. Meanwhile, geographical sciences, which have traditionally focused on the spatial consequences of human-environment ecological relations, have mainly analyzed the security dimensions of these relations in the form of critical geopolitics, so that within its framework, the government is no longer the focus of geopolitical studies, but human security beyond political borders has become the focus of research and attention in the context of the biosphere. Meanwhile, the Caspian Basin, as a region whose developments have a significant impact on relations with neighboring countries, is exposed to challenges arising from the interrelationship of security and ecological factors. The countries of this region, especially Iran, which are the platforms for the realization of these challenges, have observed the consequences that have occurred in their border areas, which are adjacent to their neighbors, and are trying to take steps to reduce them by adopting measures. In this article, the authors have used a descriptive-analytical method and library studies and survey surveys to evaluate the research hypothesis, which is "geographical factors can affect the security and ecology of the Caspian Basin countries and Guilan Province." In this regard, the theoretical foundations and some of the geographical factors of the Caspian Basin and their impact on security and ecology in this area are first described.