The present invention is particularly applicable to plastering engineering for brick-concrete mixed building. Its features are: using special combined plate ruler to set and to screed in place of such complex processes in prior art as pulling wire for screeding, making screed, to plaster for plane (faces of wall, floor and ceiling), cavity (doorway and hatch, the opening of a well etc.), projected eaves (hood, balcony, buttress, lintel, frame, jamb etc.), and thereby a transformation is caused in plastering process. While it can improve smoothness of the plastered face, it can greatly increase work efficiency and reduce work hours.