Optical microscope as a tool for modern testing, optical microscopy, photoelectric conversion technology, computer image processing technology is the perfect combination of the development of high-tech products, can be easily observed on the computer optical image, and thus the analysis of the metallographic map, rating, and the image of the output, printing. Widely used in aluminum alloy material and its extrusion product inspection. In this company, the alloy phases, crystalline structure and segregation layer of Al alloy cast rods were observed by metallographic microscope, and the quality of the products was ensured from the microstructure level.