In the 1980s and 1990s, Sullivan, an architect of Chicago School, advocated the slogan "Form follows function", arguing that "function remains unchanged, so does form".

The Chicago School represented by Sullivan is the founder of modern American architecture. Chicago School highlights the main position of function in architectural design, clearly puts forward the view that form comes from function, tries to get rid of the fetters of eclecticism, discusses the application of new technology in high-rise buildings, emphasizes that architectural art should embody the characteristics of new technology, and advocates simple facade to conform to the spirit of industrialization of the times. The heyday of Chicago School was between 1883 and 1893. Its important contribution to architectural modeling is to create the "window of Chicago", that is, to open the whole room with large glass, forming a unique style with simple facade. The important contribution in engineering technology is the creation of high-rise metal frame structure and box foundation.