The Seoul Metropolitan Subway Corp. have gradually installed screen doors in platforms of 115 subway stations in Seoul on lines 1, 2, 3, and 4. Installation in nine areas among those has been completed and screen doors are being operated as a model operation. Traffic signs should be clear for users. The essential functions of signs should be fully investigated from the aspect of user as well as the visual beauty and recognition. Signs should be able to provide users with information regarding location, position, directions, etc. Particularly, safety and convenient signs should be visually and sensually correlated. However, the entire screen doors in platforms installed in line 2 subway in Seoul are used for commercial advertisement, consequently, the functions and roles as public signs are not fulfilled aggravating inconvenience for users. In this study, cases have been studied to investigate requirements for user-oriented sign system in platform and public sign space to fulfill the functions of sign system in platform. Using an anthropometry approach, the study aimed to obtain the space to install the sign system and to systemize necessary and sufficient conditions for user-oriented system for platform in which screen doors have been installed using. The study suggests fundamental information to obtain the space of public sign system on the entire screen door.