Disclosed are an apparatus and a method for extracting circumscribed rectangles of one or more characters in a transplantable electronic document. The apparatus comprises a command and resource extraction device for extracting text-segment-related commands and original font resources; a division device for dividing the original font resources into fonts; a font replacement device for seeking fonts, and obtaining font resources after font replacement; a measurement information extraction device for extracting character shape measurement information of the characters; and a calculation device for calculating the circumscribed rectangles of the characters.