The Study of the establisment of the Islamic State by ISIS in 2014, a militant group that formed by Zarqawi in 1999 and increasingly developed and conquered territory in western Iraq and eastern Syria, After seizing territories in Iraq and Syria, they proclaimed itself as the Islamic State, recently claiming Al-Baghdadi as their caliph leader. This study aims to find out the reason why ISIS establishes an Islamic State. The writer used the contstructivism theory to help analyse the problem, and used the qualitative-descriptive method. The materials of the study are obtained through internet by collecting some data from articles, journal, papers, and books to answering the research question. The data needed for the undergraduate thesis were collected through some facts that can support the data of the research.