The tensile properties and tensile fracture of the second generation single crystal superalloy DD6 with [001], [011] and [111] orientation were studied. The results show that DD6 alloy has tensile anisotropy, when temperature is higher than 850°C the ultimate tensile strength and yield strength of DD6 alloy with [001] orientation are higher than those with [011] and [111] orientation, and there are the fracture features characteristic of quasi-cleavage and dimple in DD6 alloy with [001], [011] and [111] orientation.