The Korean War was the first direct engagement between the United States and the newfound People’s Republic of China. Yet most people just focus on the warfare itself on the peninsula but overlooked the sizzling waves of political campaigns within China. Aside from directly supporting the frontline, these domestic political campaigns served a greater goal, which is to help this newborn regime to earn its survival. That is, these political campaigns served to establish and maintain the political legitimacy of the PRC regime during its earliest years. This paper will focus on four of these political campaigns took place during the Korean War era, which were the Anti-counterrevolutionary Movement (镇压反革命运动), the Resist America Aid Korea Movement (抗美援朝运动), the Patriotic Health Movement (爱国卫生运动), and the Patriotic Convention Movement (爱国公约运动), and examine in what ways these four political movements had helped the newborn regime to gain its political legitimacy.