Ti₅₀Ni_25−XPd_25−YCu_X+Y high temperature shape memory alloys (HTSMAs) with X, Y≤10 at% have been studied by DSC, XRD, TEM/EDS, hardness and cold-rolling workability tests. Experimental results show that all these HTSMAs exhibit B2 ↔ B19 martensitic transformation with Ms temperature can be predicted by the linear regression as: Ms (K)=424.2+2.7X−9.7Y. The substitution of Ni/Pd by Cu affects the lattice constants of B19 martensite, the hardness and the cold-rolling workability which can be explained by the different atomic radii of Ni, Cu and Pd. Ti₅₀Ni₁₅Pd₂₅Cu₁₀ HTSMA annealed at 523 K up to 9 weeks and thermal-cycled up to 100 times still has quite good thermal stability. However, Ti₅₀Ni₁₅Pd₂₅Cu₁₀ HTSMA annealed in between 723 K∼923 K shows obvious decrease for both Ms temperature and ΔHc value, especially at 823 K due to Ti₂Pd and Ti(Cu,Pd)₂ precipitated during annealing.