Abstract: Characteristics of ZL101 aluminum alloy tensile fracture were studied through observation of microstructure, tensile fracture and fracture profile by scanning electron microscopy (SEM) and optical microscopy (OM). The results indicate that the ZL101 aluminum alloy tensile fracture showed quasi-cleavage characteristic with second phases (eutectic silicon and AlFeMnSi phase) distributing along the fracture. Cracks initiated in the sharp part and concave angle of second phases where stress was concentrated, and extended along them. In this process the second phases were torn or broken, and the lateral particles deformed. Ductile deformation of the brittle phase after being torn or broken created dimples; the ligulate patterns arose when the particle phase deformed after crack expansion along certain oriented crystal faces; torn edges formed if cracks extended to two cross second phases with a certain angle and the expansion direction changed obviously.