The presence of foreign companies in the city of Cilegon is a form of successful investment realization which is a government program. However, along the way, the existence of foreign companies has raised various problems that have had an impact on the economic and social life of the community. These problems ultimately created tensions and conflicts between the community and foreign companies in Cilegon City. This study aims to analyze the dynamics of conflict between communities and foreign companies in Cilegon City. Then also analyze the obstacles faced by the government. Another objective is to analyze the Cilegon City government's strategy in preventing conflicts between communities and foreign companies in order to maintain national security stability. The methodology used is a qualitative research method by collecting data through interviews, observation, and document studies. The results of the study show that (1) the dynamics of conflict between the community and foreign companies originates from the presence of foreign companies which raises problems related to labor and environmental pollution problems. (2) In an effort to carry out strategies related to conflict prevention, the government encounters obstacles, both internal and external, from parties to the conflict. (3) The strategy used by the Cilegon municipal government in preventing conflict is by approaching sources of conflict, the Cilegon municipal government also coordinates between institutions and seeks the best solutions for the community and foreign companies. In the end the municipal government of Cilegon managed to reduce the existing tensions and conflicts, so that violent conflicts did not occur in the field, these efforts also resulted in high investment realization in this city. This is the success of the Cilegon municipal government in developing its area by maintaining existing investments so that it is able to develop the community's economy which is an effort to realize stability of national security.