PURPOSE : A blueprint management internet site operation method is provided to offer a 3 dimensional drawing or enable a user to perform a simulation on a utilization of an interior space in advance by managing drawings or image data over the internet.CONSTITUTION : The method comprises steps of constructing a blueprint management web site(S1), collecting site members such as a real estate broker, an installation company, a security company or a general internet user(S2), a member accessing a server of the internet site(S3), the server guiding the member to input location data and a building name after moving the member to a drawing retrieval space(S4, S5), the server loading the corresponding blueprint data from a building management database stored at a main frame(S6), the server generating a 3 dimensional drawing on the searched building by driving a drawing generator(S7), the server displaying the generated drawing over a drawing check space(S8), and the server allowing the member to perform a space utilization simulation over the displayed drawing by driving a simulation manager(S9).? KIPO 2002