A ternary alloying element Niobium addition to the Ni-Ti shape memory alloy could optimize transformation temperatures, mechanical properties. In this paper, with the help of ambient tensile test and scan electron microscope observation, the influences of Nb-content on the mechanical properties of (Ni47Ti44)(100-x)Nb-x alloys were investigated in detail. The results indicated that both the fracture strength (sigma(b)) and the elongation (delta) decreased gradually with the increasing of the Nb content. The fracture surfaces showed the fracture character of the alloys was clearly gliding fracture, which is typically transgranular fracture mode.