Titanium alloysfind wide applications in aerospace industry for its high specific strength and good corrosion resistance. However, limited creep resistance may restrict their applications at high temperature. Experiments have demonstrated that the steady creep activation energy is close to the effective diffusion activation energy, indicating that the atomic diffusiontakesan important effect on the creep resistance. In the present work, a first-principles method is employed to study the migration energy of various alloying atoms ina-titanium. We show that, for the atoms migrating through vacancy mechanism, the in-basal-plane migration energy decreases in the order of Al, V, Ti,Sn, Ta, Mo,Nb,Zr, whereas the out-plane migration energy decreases in the order of Al, Sn, V, Ti, Ta, Mo,Nb,Zr. For the atoms (Fe, Co, Ni) migrating through interstitial mechanism, the migration energies are quite low.