Objective This study aims to observe the factors that influence the development of national identity of North Korean refugees who have resettled in South Korea. Methods The study population was comprised of 500 North Korean refugees who immigrated to South Korea in 2007. The variables measured national identity as South Korean, a scale for discrimination perceived during daily life, a social for supporting social network, a for childhood trauma experience, traumatic experiences in North Korea, and traumatic experiences during the escape process. Factor analysis was conducted on the result from the scale for national identity as South Korean which produced 4 factors including national consciousness, positive emotions, positive values, and negative values. Multiple regression was done to identify how variables such as demographic data, discrimination, social network, and past trauma had influenced each of 4 factors. Results National identity was negatively related by traumatic experience during childhood, perceived discrimination, and positively influenced by social networks. Positive emotion was related negatively to education level in North Korea and perceived discrimination, but positively related to traumatic experiences in North Korea. Negative value was related positively age and perceived discrimination but negatively related to supporting social network. Conclusion The results of this study suggests that promoting social networks, decreasing discrimination and healing past traumas were important factors for North Korean refugees in South Korea to facilitate a new national identity as a South Korean.