Tensile strength of as-cast 7005 aluminum alloy produced by electrolytic liquid Al was measured by means of room temperature tensile testing.Fracture morphology and longitudinal microstructure were observed by OM（optical microscope） and SEM（scanning electron microscope） as well as EPA（energy spectrum analysis）.The results indicate that tensile strength of as-cast 7005 alloy is distinctly dependent on the Fe

Si

H and Al2O3 inclusions in electrolytic liquid Al.Shrinkage porosity and inclusions in aluminum ingot are controlled by creation of H2 and Al2O3 inclusions in electrolytic liquid Al.The hard brittle coarse second phase

such as AlFeMnSi

Mg2Si phase

are formed by the reaction of impurity elements Fe

Si in electrolytic liquid Al with alloy elements Mn

Mg

which is distributed in grains and on the grain boundaries.The fracture of the samples is attributed to the co-action of inclusions

shrinkage porosity and brittle AlFeMnSi phases.Tensile fracture mechanism of as-cast 7005 aluminum alloy is characterized by dimple-quasi-cleavage features of trangranular model.