Provided are a graphic user interface capable of collectively and selectively changing instances using a master and a method of collectively and selectively changing instances using a master. A graphic user interface capable of collectively changing instances using a master according to an exemplary embodiment of the invention includes: a master area having masters, which are objects to be copied, defined therein; and a text editing area capable of copying the master to draw up a document. In the graphic user interface, the master area is formed in a hierarchy structure of child masters and a parent master made by combining the child masters. When a specific child master in the master area is changed, the child masters constituting the parent master that includes the specific child master are changed, and the child masters before the change and the instances linked to the text editing area by the parent master are all changed.