Many theoretical and experimental studies showed that stress triaxiality has an important influence on ductile fracture. However, recent studies showed that Lode parameter, which can be linked to normalized third stress invariant, is also an essential factor. In the present study, round notched bar and flat grooved plate specimens made of 7075 aluminum alloy were used to assess the effect of stress triaxiality and Lode parameter on ductile fracture and on theScorresponding microscopicSmechanism. Quasi-static tensile experiments and parallel numerical simulations were conducted to obtain stress triaxiality, Lode parameter and failure locus. A fractographical analysis was performed to determine the rules of void evolution under different stress states. Stress triaxiality and Lode parameter have an important influence on failure strain. The effect of Lode parameter decreased with the increases in stress triaxiality. The fractographs showed that the size of the void decreased with the increase of stress triaxiality, and the morphologies of the voids of different Lode parameters were obviously different. TheSnucleation rate and growth degree of secondary voids were also affected by Lode parameter.