Strengthening mechanism of Au990-Ti jewelry alloys has been studied systematically bY means of tensile test, hardness test, optical microscopic analysis. Results show that strengthening modes of Au990-Ti jewelry alloys mainly cover grain refining strengthening, work hardening and aging strengthening, and that their mechanical properties are superior to those of standard An917 jewelry alloys, that is, An917Ag55Cu28 and Au917Ag32Cu51. In addition, Au990-Ti jewelry alloys are of better cold workability than pure gold, because of high hardness and strength, good ductility in the solid solution state.