This study used Space Syntax to analyze the spatial structure of Seoul and Pyongyang, and to find out the impact of each system on urban space over the past 50 years. To this end, we analyze the uses and facilities around major roads along with spatial syntax variables derived based on the road networks of the two cities. According to the analysis, Seoul has a multi-nuclear structure and has an efficient and reasonable road network system compared to Pyongyang. However, in the larger category, inter-connectivity was low and forming a deeper urban structure compared to Pyongyang. Pyongyang has a single nuclear structure, and has a low connection and deep spatial structure in the local range. Pyongyang's phase-centered core had a number of ideological-leaning streets, and the roads had greater influence around it. The spatial scope covered in this study was limited, and there is another limit to the difficulty of reflecting accurate North Korean information. However, it is meaningful that the urban structure of Seoul and Pyongyang was quantitatively compared and analyzed, and the spatial structure of each city was examined through the functions and tendencies of major streets. Recognizing the spatial difference between the two cities derived from the results of this study, It is expected to help Seoul and Pyongyang prepare for expansion of exchanges and establish urban space policies.