The elastic properties of titanium alloys are not only affected by heat treatment processes, but also by their composition and structure. For example, the elastic modulus of high-purity Ti varies depending on its alloy type, ranging from approximately 93 to 120.5 GPa. Based on the constitutive model of multi-scale elastic response, for example, the effective elastic response of alpha+beta titanium alloy with different contents under load was theoretically predicted and the effective elastic properties of titanium alloys were calculated, such as effective elastic modulus E ? , effective bulk modulus K ?, effective shear modulus G ? and effective Poisson"s ratio ν ?, the mechanism of the effect of contents on the effective elastic properties of titanium alloy was also revealed. The comparison with different micromechanical models and experimental measurements were shown that the E ? of titanium alloy was affected by α phase, and approximately decreased from 111.11 GPa to 87.49 GPa as α phase; K ?, G ?, and ν ? were affected by β phase, K ? approximately increased from 104.12 GPa to 117.21 GPa, K ? approximately decreased from 42.02 GPa to 31.81 GPa, and ν ? approximately increased from 0.322 to 0.376, the accuracy of which was confirmed by the consistence with experimental measurements.