The effects of 2at.% Ga addition on the microstructure and mechanical properties of the TiCu-base nano/ultrafine bimodal structured alloy were investigated systematically through XRD, OM, compressive test and SEM. The results showed that constitutional phases were changed from bcc -Ti(M) to unknown nanostructure + bcc -Ti(M), content of nanostructured matrix is increased, the calculated mean crystalline size was decreased from 12.6 to 11.7nm, and also, the yield and maximum strengths and plasticity were enhanced markedly. The reasons, which caused these phenomenons, were discussed.