The influence of forging and aging treatment on mechanical properties and microstructure of large size prestretched thick plate of 7B04 aluminium alloy was investigated through tensile test, corrosion test, transmission electronic microcopy (TEM) and energy dispersive spectrum (EDS) analysis. The results show that the properties of plate performed extra forging (FSR technology) are much higher than those of plate without forging (CSR technology). T7451 temper is preferred to resisting corrosion than T651 temper due to a wide PFZ and discontinuous grain boundary precipitates.