The tensile properties and fracture modes of a new nickel-based single crystal superalloy were investigated. Tensile specimens were prepared from the single-crystal with orientation, whose growth direction was parallel to the loading axis in tension. The fractograph was examined by means of scanning electron microscope. The results show that the tensile and yield strength increased first and then decreased with the test temperature increasing, and they reached the peak values at 760℃ and 850℃ respectively, while the elongation and the area reduction decreased gradually from room temperature to 760℃ and then they increased rapidly at temperatures above 760℃. At 850℃, the elongation attained a maximum and then dropped gradually with a rise of temperature up to 960℃. The deformation mechanism of the alloy was transformed from semi-brittleness into plasticity, which happens at 980℃.