The influence of hot forging treatment on microstructure and mechanical properties of 5A06T6 extruded aluminum alloy were analyzed by mechanical testing machine, OM, SEM and TEM. The results show that the grains in the 5A06T6 extruded aluminum alloy after hot forging are obviously refined to form dense structure. Meanwhile, the number of pores in adjacent grains is significantly reduced, and many grains of different sizes are generated in the alloy. After the hot forging of alloy, the black precipitated phase has obvious aggregation, and there is no pore structure in the microstructure. After hot extrusion and hot forging samples are subjected to T6 peak aging treatment, no significant PFZ phenomenon occurs. However, the tensile strength and yield strength decrease slightly, and the elongation, hardness and conductivity of hotforging alloy increase slightly. Furthermore, more dimples are formed in the fracture area of hotforged alloy than that of extruded alloy, and these dimples are basically distributed in the gap between tearing edges, and the number of tearing edges of alloy increases significantly.