The microstructure and mechanical properties of novel β-type Ti 74- x Nb 26 Ni x ( x = 4, 8, 12, 16, 20, and 24 at.%) alloys with a low Young's modulus and containing different amounts of a second phase (Ti 2 Ni and Ni 3 Nb) were investigated. The experimental results show that the relative volume fractions of Ti 2 Ni phase in the Ti–Nb–Ni alloys increased with increasing Ni content. The mechanical properties of Ti–Nb–Ni alloys varied with the amount of second phase. Ti 70 Nb 26 Ni 4 , Ti 66 Nb 26 Ni 8 , and Ti 62 Nb 26 Ni 12 alloys containing a small amount of Ti 2 Ni phase exhibited a higher plastic strain; however, Ti 58 Nb 26 Ni 16 , Ti 54 Nb 26 · Ni 20 , and Ti 50 Nb 26 Ni 24 alloys containing a large amount of Ti 2 Ni phase and a small amount of Ni 3 Nb phase exhibited a small plastic strain. The increase in strength and decrease in plasticity of alloys can be mainly attributed to the increase in high-strength brittle Ti 2 Ni phase and grain refining of the β-phase matrix. In addition, Ti 50 Nb 26 Ni 24 alloy with a low Young's modulus has a high yield strength and elastic energy; this has potential application as biomedical and functional materials.