In this paper phase stability and functional properties of Pd-doped NiTi with different Pd concentrations (Ni24-nPdnTi24, n=2, 3, 4, 5, 6, 9, 12; CPd=4.2 at.%, 6.3 at.%, 8.4 at.%, 10.4 at.%, 12.5 at.%, 18.8 at.% and 25 at.%) are calculated by first-principles method. Results show that B19' is the most stable when CPd is less than 10.4 at.%, whereas B19 is the most stable for CPd is equal to or larger than 10.4 at.%. The formation energy decreases with increasing Pd concentration. With increasing CPd, the energy difference between austenite and martensite decreases slightly and increases for CPdCPdCPd=10.4 at.%, which agrees well with the experimental results.