Orthography is a basic theory for drawing the “engineering drawing”, and orthographic drawing is the major design to show engineering objects. Turnning the 2D graph into the 3D one quickly and rationally by using certain reading methods is a basic skill for every engineers and technicians, and it is an effective tool for them to understand the design intention. Three methods for reading orthographic drawing were proposed in the paper to provide a reference for teachers, which were analytical method of shape, analytical method of line and plane, and boxing method.