This research looks at the initial stage of JCS, ROIC As the ROK forces were expanded and various agencies were formed in the Korean War, the need for an organization to determine an united strategic policy was raised. Already with the establishment of the government, the Ministry of National Defense envisioned the JCS’ role. After the armistice, the JCS, which had been an advisory body for the Ministry of National Defense, was reorganized into the Combined Chiefs of Staff(CCS) directly under the president in Feb. 1954, responding to issues such as the withdrawal of U.S. forces from Korea and the reinforcement of Korean forces. The CCS emphasized the importance of the joint strategic operations of the triservice by holding regular and ad-hoc meetings, including strengthening the headquarters' own organization and securing facilities. President Syngman Rhee participated in the meeting to raise the status of CCS. However, due to political upheaval, the difficulties were compounded by the frequent replacement of the head office. When ROK army was maintained by U.S. military aid, the CCS was criticized as a rooftop, saying that each service had a staff organization. Under these constraints, the CCS did not reach the point of carrying out training, operational command, and supervision of each force, but it could be evaluated as having performed its initial role, such as the direction of military power building and the establishment of basic strategic policies. The government's response and negotiating power were also enhanced on the issues such as the withdrawal of U.S. troops, the reinforcement and reduction of Korean forces, and the peace line with Japan.