To software development and technology research, logical model visualization has an important significance. This paper puts forward an ER-diagram automatic drawing technology based on graph grammar-directed, and expands graph grammar named ER graph grammar. It overcomes the shortcoming of limited map number for drawing ERdiagram and difficult changing in original modeling tools, and describes relationship of entities and drawing rules of ER-diagram on the semantic. ER-diagram automatic placement and automatic wiring are presented, and ER-diagram automatic drawing is realized.