Mechanical Property and elastic modulus of Ti-Nb based alloys with various Si content, prepared by water quenching from high temperature β phase field, cold rolling and recrystallization heat treatment followed by water quenching, were investigated in terms of tensile test and resonance vibration method. TEM observations revealed that in addition to orthorhombic structured α" phase and bcc structured β phase, an intermediate ω phase is characterized in the microstructure. The volume fraction ratio of constituent phases was dependent upon Nb and Si contents. In as-quenched samples yield strength increased with increasing Si content. This propensity was similar to the cold rolled alloys. In recrystallized samples however, yield strength decreased slightly with increasing Si content even though the alloy containing higher Si content showed smaller grain size. From these results, it is found that strength of the present alloy influences largely on solid solution hardening and phase stability but does weakly on grain size. Yield strength of cold rolled sample was higher than as-quenched and recrystallized samples. Elastic modulus values were measured to 55GPa, 63GPa and 44GPa for as-quenched, cold rolled and recrystallized samples, respectively. The variations of yield strength and elastic modulus values were interpreted in terms of changes in microstructure as well as grain size and phase stability.