Abstract: With the increasing demand for thin-walled extruded profiles, it is necessary to understand the metal flow of aluminum bars and the metal flow into the die holes. Through the experimental method, the metal flow of aluminum profile extruded with simple thin-walled section is discussed.The results show that different flow patterns and material properties can be obtained by changing extrusion speed, temperature and wall thickness. The experiment provides the technology of using the contour map to represent the metal flow under different magnification; in different stages of extrusion, the state of the metal in the process of extrusion can be understood by testing the grain size, shape and orientation. Through the experiment, the main factors influencing the metal flow in the extrusion process of thin-walled section are obtained.