This study aims to investigate representation difference and its significance by visual switching genre. In order to study successful examples of genre visual switching from documentary to film, documentary <Silmido Special Forces> and film <Silmido> were analyzed regarding their story structures and discourses. And internal factors that enabled successful visual genre switching were investigated. As a result, both similarities and differences were uncovered in story structures and discourses of the two works. The documentary <Silmido Special Forces> demands confession of historical truth and reflection of the state power, while the film <Silmido> discloses violence of the state power against its citizens based on the true story. The two works display distinctive narrative structures of binomial confrontation and storytelling strategies with the course of time. However, there are substantial differences in the manner of representation and the length of the works. In other words, the documentary stresses reliability and authenticity of historical facts by interviews with people who were involved and experts, while the film weighs on cinematic quality for the public by reproducing historical facts stereoscopically and in depth with appropriate fictions. On the other hand, better realism, perfect configuration, spectacular image reproduction, simple story, and star director/actor were identified as important internal factors for the successful visual genre switch from documentary to film.