Abstract: Based on the 6 series aluminum alloy often used in transportation, construction field and mechanical equipment, in order to further improve the mechanical properties of Al-Mg-Si alloy plate, the influence of Mo microalloying on the microstructure and performance of Al-Mg-Si alloy was studied by adding Mo element. Six kinds of Al-Mg-Si alloys with different Mo content were designed and prepared, and the microscopic structure and short-term high-temperature mechanical properties of the rolled plates of each alloy were detected and analyzed by direct-reading spectroscopy,metallographic microscopy, scanning electron microscopy, X-ray diffractometer, tensile testing machine and other equipment.The results show that the Mo element added to the Al-Mg-Si alloy has a certain effect on hindering the growth of recrystallization, and the effect is most obvious when the Mo content is 0.39%, the alloy has the best organization and mechanical properties, and its room temperature tensile strength reaches 278 MPa, which is about 85% higher than that of the alloy without the addition of molybdenum.