In the present study, Ni-W-Cr-P quaternary alloy coatings were prepared on titanium-based alloys by electroless deposition. The morphology, crystal structure, microhardness, and corrosion resistance of samples were studied by scanning electron microscope (SEM), X-ray diffractometer (XRD), microhardness tester, and electrochemical analyzer. The results show that the microstructure of these alloy films changes with the increase of annealing temperature. As-deposited alloy layers belong to nickel-based mischcrystal structure, and its crystallinity was enhanced to 200 C and 300 C, gradually; the new phase Ni 3 P began to P generated. Because of the different structures after annealing, microhardness and corrosion resistance of the alloy coatings possess a relevant change. The Ni-W-Cr-P alloy coatings heated at 600 C exhibit better microhardness and corrosion resistance than those of samples at other annealing temperature. The related mechanisms of those results were also discussed, briefly.