The invention discloses a nickel-rich nickel-titanium-based alloy high in hardness, low in elastic modulus, resistant to frictional wear, low in density, nonmagnetic and resistant to corrosion. On the basis of a nickel-rich Ni-Ti binary alloy system, elements of Al, Nb, Hf, Ta, Zr, Mo and Co (X group elements) or combinations of the elements of Al, Nb, Hf, Ta, Zr, Mo and Co (X group elements) replacing Ti positions in the Ni-Ti alloy are added. Or on the basis of the nickel-rich Ni-Ti binary alloy system, elements of Cu, Fe, Cr, Mo and Co (Y group elements) or combinations of the elements of Cu, Fe, Cr, Mo and Co (Y group elements) replacing Ni positions in the Ni-Ti alloy are added. Or on the basis of the nickel-rich Ni-Ti binary alloy system, the above alloy elements or the combinations of the alloy elements replacing the Ti positions and the Ni positions in the Ni-Ti alloy are added at the same time. Main strengthened phases of the alloy are nanometer Ni4Ti3 phases, the volume fraction is 30-80 Vol%, and the alloy hardness is not lower than 600 HV.